Imaging apparatus

ABSTRACT

An imaging apparatus with improved convenience, which can perform various types of processing using an imaging device while performing phase difference detection, is provided. 
     An imaging unit ( 1 ) includes an imaging device ( 10 ) for performing photoelectric conversion to convert light into an electrical signal, the imaging device ( 10 ) configured so that light passes through the imaging device ( 10 ), a phase difference detection unit ( 20 ) for receiving the light having passed through the imaging device ( 10 ) to perform phase difference detection, a focus lens group ( 72 ) for adjusting a focus position, and a body control section ( 5 ) for controlling the imaging device ( 10 ) and controlling driving of the focus lens group ( 72 ) at least based on a detection result of the phase difference detection unit. The body control section ( 5 ) performs a focus operation based on a detection result of the phase difference detection unit during exposure of the imaging device.

TECHNICAL FIELD

The present invention relates to an imaging apparatus including animaging device for performing photoelectric conversion.

BACKGROUND ART

In recent years, digital cameras that convert an object image into anelectrical signal using an imaging device such as a charge coupleddevice (CCD) image sensor, a complementary metal-oxide semiconductor(CMOS) image sensor or the like, digitizes the electrical signal, andrecords the obtained digital signal have been widely used.

Single-lens reflex digital cameras include a phase difference detectionsection for detecting a phase difference between object images, and havethe phase difference detection AF function of performing autofocusing(hereinafter also simply referred to as “AF”) by the phase differencedetection section. Since the phase difference detection AF functionallows detection of defocus direction and defocus amount, the movingtime of a focus lens can be reduced, thereby realizing fast-focusing(see, for example, Patent Document 1). In known single-lens reflexdigital cameras, provided is a movable mirror capable of moving in orout of an optical path from a lens tube to an imaging device in order toguide light from an object to a phase difference detection section.

In so-called compact digital cameras, the autofocus function by video AFusing an imaging device (see, for example, Patent Document 2) isemployed. Therefore, in compact digital cameras, a mirror for guidinglight from an object to a phase difference detection section is notprovided, thus achieving reduction in the size of compact digitalcameras. In such compact digital cameras, autofocusing can be performedwith light incident on the imaging device, i.e., with the imaging devicebeing exposed to light. That is, it is possible to perform various typesof processing using the imaging device, including, for example,obtaining an image signal from an object image formed on the imagingdevice to display the object image on an image display section providedon a back surface of the camera or to record the object image in arecording section, while performing autofocusing. In general, thisautofocus function by video AF advantageously has higher accuracy thanthat of phase difference detection AF.

CITATION LIST Patent Document

-   PATENT DOCUMENT 1: Japanese Patent Application No. 2007-163545-   PATENT DOCUMENT 2: Japanese Patent Application No. 2007-135140

SUMMARY OF THE INVENTION Technical Problem

However, as in a digital camera according to PATENT DOCUMENT 2, adefocus direction cannot be instantaneously detected by video AF. Forexample, when contrast detection AF is employed, a focus is detected bydetecting a contrast peak, but a contrast peak direction, i.e., adefocus direction cannot be detected unless a focus lens is shifted toback and forth from its current position, or the like. Therefore, ittakes a longer time to detect a focus. In view of reducing a timerequired for detecting a focus, phase difference detection AF is moreadvantageous. However, in an imaging apparatus such as a single-lensreflex digital camera according to Patent Document 1 employing phasedifference detection AF, a movable mirror has to be moved to be on anoptical path from a lens tube to an imaging device in order to guidelight from an object to a phase difference detection section. Thus,various types of processing using the imaging device, such as, forexample, exposure of the imaging apparatus cannot be performed whilephase difference detection AF is performed. Also, the movable mirror hasto be moved when an optical path of incident light is switched between apath toward the phase difference detection section and a path toward theimaging device. Thus, disadvantageously, a time lag and noise aregenerated by moving the movable mirror.

That is, a known imaging apparatus for performing phase differencedetection AF has been not convenient in relation to performing varioustypes of processing using the imaging apparatus.

In view of the above-described points, the present invention has beendevised, and it is therefore an object of the present invention toimprove the convenience of an imaging apparatus including an imagingdevice and a phase difference detection section in relation toperforming various types of processing using the imaging device andphase difference detection using the phase difference detection section.

Solution to the Problem

An imaging apparatus according to the present invention includes animaging device for performing photoelectric conversion to convert lightinto an electrical signal, the device being configured so that lightpasses through the imaging device, a phase difference detection sectionfor receiving light which has passed through the imaging device toperform phase difference detection, a focus lens for adjusting a focusposition, and a control section for controlling the imaging device andcontrolling driving of the focus lens at least based on a detectionresult of the phase difference detection section to adjust the focusposition.

An imaging apparatus according to another aspect of the presentinvention has been devised to realize fast-focusing on an image objectwhile performing exposure of the imaging device. Specifically, theimaging apparatus includes an imaging device for performingphotoelectric conversion to convert light into an electrical signal, thedevice being configured so that light passes through the imaging device,a phase difference detection section for receiving light which haspassed through the imaging device to perform phase difference detection,a focus lens for adjusting a focus position, and a control section forcontrolling driving of the focus lens based on a detection result of thephase difference detection section to perform a focus operation to focusan image object on the imaging device, and the control section performsthe focus operation based on the detection result of the phasedifference detection section during exposure of the imaging device.

Advantages of the Invention

According to the present invention, an imaging device configured so thatlight passes through the imaging device, and a phase differencedetection section for receiving light which has passed through theimaging device to perform phase difference detection are provided.Moreover, a control section controls the imaging device and alsocontrols driving of the focus lens at least based on a detection resultof the phase difference detection section. Thus, phase differencedetection can be performed by the phase difference detection sectionusing light which has passed through the imaging device, while causinglight to enter the imaging device to perform various types of processingusing the imaging device. Accordingly, various types of processing usingthe imaging device can be performed in parallel with phase differencedetection by the phase difference detection section, or, switchingbetween various types of processing using the imaging device and phasedifference detection by the phase difference detection section can beperformed quietly and quickly, so that the convenience of the imagingdevice can be improved.

According to another aspect of the present invention, an imaging deviceconfigured so that light passes through the imaging device, and a phasedifference detection section for receiving light which has passedthrough the imaging device to perform phase difference detection areprovided. Thus, phase difference detection can be performed by the phasedifference detection section using light which has passed through theimaging device to focus an image object on the imaging device, whileperforming exposure of the imaging device. Accordingly, the imagingobject can be quickly focused while the imaging device is exposed tolight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a camera according to a first embodiment ofthe present invention.

FIG. 2 is a cross-sectional view of an imaging unit.

FIG. 3 is a cross-sectional view of an imaging device.

FIG. 4 is a plan view of the imaging device.

FIG. 5 is a plan view of a phase difference detection unit.

FIG. 6 is a schematic perspective view of an imaging unit according to avariation.

FIG. 7 is a cross-sectional view of an imaging device according to thevariation.

FIG. 8 is a cross-sectional view of an imaging device according toanother variation.

FIG. 9 is a cross-sectional view illustrating a cross section of animaging unit according to the another variation, which corresponds toFIG. 2.

FIG. 10 is a cross-sectional view illustrating a cross section of theimaging unit of the another variation, which is perpendicular to thecross section corresponding to FIG. 2.

FIG. 11 is a flowchart of the steps in a shooting operation using phasedifference detection AF before the release button is pressed all the waydown.

FIG. 12 is a flowchart showing the basic steps in each of shootingoperations including a shooting operation using phase differencedetection AF after the release button is pressed all the way down.

FIG. 13 is a flowchart of the steps in a shooting operation usingcontrast detection AF before the release button is pressed all the waydown.

FIG. 14 is a flowchart of the steps in a shooting operation using hybridAF before the release button is pressed all the way down.

FIG. 15 is a flowchart of the steps in a shooting operation using phasedifference detection AF according to the variation before the releasebutton is pressed all the way down.

FIG. 16 is a flowchart of the steps in a shooting operation using hybridAF according to the variation before the release button is pressed allthe way down.

FIG. 17 is a flowchart of the steps in a shooting operation in acontinuous shooting mode before the release button is pressed all theway down.

FIG. 18 is a flowchart of the steps in a shooting operation in thecontinuous shooting mode after the release button is pressed all the waydown.

FIG. 19 is a flowchart of the steps in a shooting operation in a lowcontrast mode before the release button is pressed all the way down.

FIG. 20 is a flowchart of the steps in a shooting operation of changingAF function according to a type of an interchangeable lens before therelease button is pressed all the way down.

FIG. 21 is a flowchart of the steps in a shooting operation in aduring-exposure AF shooting mode before the release button is pressedall the way down.

FIG. 22 is a flowchart of the steps in a shooting operation in theduring-exposure AF shooting mode after the release button is pressed allthe way down.

FIG. 23 is a block diagram of a camera according to a second embodimentof the present invention.

FIGS. 24(A) through 24(C) are perspective views illustrating aconfiguration of a quick return mirror and a shielding plate. FIG. 24(A)illustrates the quick return mirror in a retracted position. FIG. 24(B)illustrates the quick return mirror in a position between the retractedposition and a reflection position. FIG. 24(C) illustrates the quickreturn mirror in the reflection position.

FIG. 25 is a flowchart of the steps in a finder shooting mode before therelease button is pressed all the way down.

FIG. 26 is a flowchart of the steps in the finder shooting mode afterthe release button is pressed all the way down.

FIG. 27 is a flowchart of the steps in a live view shooting mode beforethe release button is pressed all the way down.

FIG. 28 is a flowchart of the steps in the live view shooting mode afterthe release button is pressed all the way down.

DESCRIPTION OF REFERENCE CHARACTERS

-   -   1, 401 Imaging Unit    -   10, 210, 310 Imaging Device    -   20, 420 Phase Difference Detection Unit (Phase Difference        Detection Section)    -   4 Camera Body (Imaging Apparatus Body)    -   40 e During-Exposure AF Setting Switch (Setting Switch)    -   44 Image Display Section    -   46 Quick Return Mirror (Movable Mirror)    -   47 Shielding Plate (Shielding Section)    -   5 Body Control Section (Control Section, Distance Detection        Section)    -   6 Finder Optical System    -   7 Interchangeable Lens    -   72 Focus Lens Group (Focus Lens)    -   73 Aperture Section (Light Amount Adjustment Section)    -   100, 200 Camera (Imaging Apparatus)

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described hereinafter indetail with reference to the accompanying drawings.

First Embodiment

A camera as an imaging apparatus according to a first embodiment of thepresent invention will be described.

As shown in FIG. 1, a camera 100 according to the first embodiment is asingle-lens reflex digital camera with interchangeable lenses andincludes, as major components, a camera body 4 having a major functionas a camera system, and interchangeable lenses 7 removably attached tothe camera body 4. The interchangeable lenses 7 are attached to a bodymount 41 provided on a front face of the camera body 4. The body mount41 is provided with an electric contact piece 41 a.

—Configuration of Camera Body—

The camera body 4 includes the imaging unit 1 for capturing an objectimage as a shooting image, a shutter unit 42 for adjusting an exposurestate of the imaging unit 1, an optical low pass filter (OLPF) 43,serving also as an IR cutter, for removing infrared light of the objectimage entering the imaging unit 1 and reducing the moire phenomenon, animage display section 44, comprised of a liquid crystal monitor, fordisplaying a shooting image, a live view image and various pieces ofinformation, and a body control section 5. The camera body 4 serves asan imaging apparatus body.

In the camera body 4, a power switch 40 a for turning on/off the camerasystem, a release button 40 b operated by a user when the user performsfocusing and releasing operations, and setting switches 40 c and 40 ffor turning on/off various shooting modes and functions.

When the camera system is turned on by the power switch 40 a, power issupplied to each part of the camera body 4 and the interchangeable lens7.

The release button 40 b operates as a two-stage switch. Specifically,autofocusing, AE (Automatic Exposure) or the like, which will bedescribed later, is performed by pressing the release button 40 bhalfway down, and releasing is performed by pressing the release button40 b all the way down.

An AF setting switch 40 c is a switch for switching an autofocusfunction from one to another of three autofocus functions, which will bedescribed later. The camera body 4 is configured so that the autofocusfunction is set to be one of the three autofocus functions by switchingthe AF setting switch 40 c.

A continuous shooting mode setting switch 40 d is a switch forsetting/canceling a continuous shooting mode, which will be describedlater. The camera body 4 is configured so that a shooting mode can beswitched between a normal shooting mode and a continuous shooting modeby operating the continuous shooting mode setting switch 40 d.

A during-exposure AF setting switch 40 e is a switch for turning on/offduring-exposure AF, which will be described later. The camera body 4 isconfigured so that the shooting mode is switched between aduring-exposure AF shooting mode in which exposure is performed whileautofocusing is performed and a normal shooting mode in which the focuslens group 72 is halted and autofocusing is not performed while exposureis performed by operating the during-exposure AF setting switch 40 e.The during-exposure AF setting switch 40 e serves as a setting switchfor switching the shooting mode between the during-exposure focusingshooting mode and the normal shooting mode.

A macro setting switch 40 f is a switch for setting/canceling a macroshooting mode, which will be described later. The camera body 4 isconfigured so that the shooting mode is switched between the normalshooting mode and the macro shooting mode which is suitable for close-upshooting by operating the macro setting switch 40 f.

Clearly, the setting switches 40 c-40 f may be selection items in a menufor selecting various camera shooting functions.

Furthermore, the macro setting switch 40 f may be provided to theinterchangeable lens 7.

The imaging unit 1, which will be described in detail later, performsphotoelectric conversion to convert an object image into an electricalsignal. The imaging unit 1 is configured to be movable in a planeperpendicular to an optical axis X by a blur correction unit 45.

The body control section 5 includes a body microcomputer 50, anonvolatile memory 50 a, a shutter control section 51 for controllingdriving of the shutter unit 42, an imaging unit control section 52 forcontrolling the operation of the imaging unit 1 and performing A/Dconversion of an electrical signal from the imaging unit 1 to output theconverted signal to the body microcomputer 50, an imagereading/recording section 53 for reading image data from, for example, acard type recording medium or an image storage section 58 which is aninternal memory and recording image data in the image storage section58, an image recording control section 54 for controlling the imagereading/recording section 53, an image display control section 55 forcontrolling display of the image display section 44, a blur detectionsection 56 for detecting an amount of an image blur generated due toshake of the camera body 4, and a correction unit control section 57 forcontrolling the blur correction unit 45. The body control section 5serves as a control section.

The body microcomputer 50 is a control device for controlling corefunctions of the camera body 4, and performs control of varioussequences. The body microcomputer 50 includes, for example, a CPU, a ROMand a RAM. Programs stored in the ROM are read by the CPU, and thereby,the body microcomputer 50 can execute various functions.

The body microcomputer 50 is configured to receive input signals fromthe power switch 40 a, the release button 40 b and each of the settingswitches 40 c and 40 f and output control signals to the shutter controlsection 51, the imaging unit control section 52, the imagereading/recording section 53, the image recording control section 54,the correction unit control section 57 and the like, thereby causing theshutter control section 51, the imaging unit control section 52, theimage reading/recording section 53, the image recording control section54, the correction unit control section 57 and the like to executerespective control operations. The body microcomputer 50 performsinter-microcomputer communication with a lens microcomputer 80, whichwill be described later.

For example, according to an instruction of the body microcomputer 50,the imaging unit control section 52 performs A/D conversion of anelectrical signal from the imaging unit 1 to output the converted signalto the body microcomputer 50. The body microcomputer 50 performspredetermined image processing to the received electrical signal togenerate an image signal. Then, the body microcomputer 50 transmits theimage signal to the image reading/recording section 53, and alsoinstructs the image recording control section 54 to record and displayan image, and thereby, the image signal is stored in the image storagesection 58 and is transmitted to the image display control section 55.The image display control section 55 controls the image display section44 based on the transmitted image signal to cause the image displaysection 44 to display an image.

The body microcomputer 50, which will be described in detail later, isconfigured to detect an object point distance to the object via a lensmicrocomputer 80.

In the nonvolatile memory 50 a, various pieces of information (unitinformation) for the camera body 4 are stored. The unit informationincludes, for example, model information (unit specific information)provided to specify the camera body 4, such as name of a manufacturer,production date and model number of the camera body 4, versioninformation for software installed in the body microcomputer 50 andfirmware update information, information regarding whether or not thecamera body 4 includes sections for correcting an image blur, such asthe blur correction unit 45, the blur detection section 56 and the like,information regarding a detection performance of the blur detectionsection 56, such as a model number, detection capability and the like,error history and the like. Such information as listed above may bestored in a memory section of the body microcomputer 50, instead of thenonvolatile memory 50 a.

The blur detection section 56 includes an angular velocity sensor fordetecting the movement of the camera body 4 due to hand shake and thelike. The angular velocity sensor outputs a positive/negative angularvelocity signal according to the direction in which the camera body 4 ismoved, using as a reference an output in a state where the camera body 4stands still. In this embodiment, two angular velocity sensors areprovided to detect two directions, i.e., a yawing direction and apitching direction. After being subjected to filtering, amplificationand the like, the output angular velocity signal is converted into adigital signal by the A/D conversion section, and then, is given to thebody microcomputer 50.

—Configuration of Interchangeable Lens—

The interchangeable lens 7 serves as an imaging optical system forforming an object image on the imaging unit 1 in the camera body 4, andincludes, as major components, a focus adjustment section 7A forperforming focusing, an aperture adjustment section 7B for adjusting anaperture, a lens image blur correction section 7C for adjusting anoptical path to correct an image blur, and a lens control section 8 forcontrolling an operation of the interchangeable lens 7.

The interchangeable lens 7 is attached to the body mount 41 of thecamera body 4 via a lens mount 71. The lens mount 71 is provided with anelectric contact piece 71 a which is electrically connected to theelectric contact piece 41 a of the body mount 41 when theinterchangeable lens 7 is attached to the camera body 4.

The focus adjustment section 7A is comprised of a focus lens group 72for adjusting focus. The focus lens group 72 is movable in the directionalong the optical axis X in a zone from a closest focus positionpredetermined as a standard for the interchangeable lens 7 to aninfinite focus position. When a focus position is detected using acontrast detection method, which will be described later, the focus lensgroup 72 has to be movable forward and backward from a focus position inthe direction along the optical axis X. Therefore, the focus lens group72 has a lens shift margin zone which allows the focus lens group 72 tomove forward and backward in the direction along the optical axis X to afurther distance beyond the zone ranging from the closest focus positionto the infinite focus position. Note that the focus lens group 72 doesnot have to be comprised of a plurality of lenses, but may be comprisedof a single lens.

The aperture adjustment section 7B is comprised of an aperture section73 for adjusting an aperture. The aperture section 73 serves as a lightamount adjustment section.

The lens image blur correction section 7C includes a blur correctionlens 74, and a blur correction lens driving section 74 a for moving theblur correction lens 74 in a plane perpendicular to the optical axis X.

The lens control section 8 includes a lens microcomputer 80, anonvolatile memory 80 a, a focus lens group control section 81 forcontrolling an operation of the focus lens group 72, a focus drivingsection 82 for receiving a control signal of the focus lens groupcontrol section 81 to drive the focus lens group 72, an aperture controlsection 83 for controlling an operation of the aperture section 73, ablur detection section 84 for detecting a blur of the interchangeablelens 7, and a blur correction lens unit control section 85 forcontrolling the blur correction lens driving section 74 a.

The lens microcomputer 80 is a control device for controlling corefunctions of the interchangeable lens 7, and is connected to eachComponent mounted on the interchangeable lens 7. Specifically, the lensmicrocomputer 80 includes a CPU, a ROM, and a RAM and, when programsstored in the ROM are read by the CPU, various functions can beexecuted. For example, the lens microcomputer 80 has the function ofsetting a lens image blur correction system (the blur correction lensdriving section 74 a or the like) to be a correction possible state or acorrection impossible state, based on a signal from the bodymicrocomputer 50. Due to the contact of the electric contact piece 71 aprovided to the lens mount 71 with the electric contact piece 41 aprovided to the body mount 41, the body microcomputer 50 is electricallyconnected to the lens microcomputer 80, so that information can betransmitted/received between the body microcomputer 50 and the lensmicrocomputer 80.

In the nonvolatile memory 80 a, various pieces of information (lensinformation) for the interchangeable lens 7 are stored. The lensinformation includes, for example, model information (lens specificinformation) provided to specify the interchangeable lens 7, such asname of a manufacturer, production date and model number of theinterchangeable lens 7, version information for software installed inthe lens microcomputer 80 and firmware update information, andinformation regarding whether or not the interchangeable lens 7 includessections for correcting an image blur, such as the blur correction lensdriving section 74 a, the blur detection section 84, and the like. Ifthe interchangeable lens 7 includes sections for correcting an imageblur, the lens information further includes information regarding adetection performance of the blur detection section 84 such as a modelnumber, detection capability and the like, information regarding acorrection performance (a lens side correction performance information)of the blur correction lens driving section 74 a such as a model number,a maximum correctable angle and the like, version information forsoftware for performing image blur correction, and the like.Furthermore, the lens information includes information (lens side powerconsumption information) regarding necessary power consumption fordriving the blur correction lens driving section 74 a, and information(lens side driving method information) regarding a method for drivingthe blur correction lens driving section 74 a. The nonvolatile memory 80a can store information transmitted from the body microcomputer 50. Theinformation listed above may be stored in a memory section of the lensmicrocomputer 80, instead of the nonvolatile memory 80 a.

The focus lens group control section 81 includes an absolute positiondetection section 81 a for detecting an absolute position of the focuslens group 72 in the direction along the optical axis, and a relativeposition detection section 81 b for detecting a relative position of thefocus lens group 72 in the direction along the optical axis. Theabsolute position detection section 81 a detects an absolute position ofthe focus lens group 72 provided in a case of the interchangeable lens7. For example, the absolute position detection section 81 a iscomprised of a several-bit contact-type encoder substrate and a brush,and is capable of detecting an absolute position. The relative positiondetection section 81 b cannot detect the absolute position of the focuslens group 72 by itself, but can detect a moving direction of the focuslens group 72. The relative position detection section 81 b employs, forexample, a two-phase encoder. As for the two-phase encoder, two rotarypulse encoders, two MR devices, two hall devices, or the like, foralternately outputting binary signals with an equal pitch according tothe position of the focus lens group 72 in the direction along theoptical axis are provided so that the phases of their pitches aredifferent from each other. The lens microcomputer 80 calculates therelative position of the focus lens group 72 in the direction along theoptical axis from an output of the relative position detection section81 b.

The blur detection section 84 includes an angular velocity sensor fordetecting the movement of the interchangeable lens 7 due to hand shakeand the like. The angular velocity sensor outputs a positive/negativeangular velocity signal according to the direction in which theinterchangeable lens 7 moves, using as a reference an output in a statewhere the interchangeable lens 7 stands still. In this embodiment, twoangular velocity sensors are provided to detect two directions, i.e., ayawing direction and a pitching direction. After being subjected tofiltering, amplification and the like, the output angular velocitysignal is converted into a digital signal by the A/D conversion section,and then, is given to the lens microcomputer 80.

A blur correction lens unit control section 85 includes a moving amountdetection section (not shown). The moving amount detection section is adetection section for detecting an actual moving amount of the blurcorrection lens 74. The blur correction lens unit control section 85performs feedback control of the blur correction lens 74 based on anoutput of the moving amount detection section.

An example in which the blur detection sections 56 and 84 and the blurcorrection units 45 and 74 a are provided to both of the camera body 4and the interchangeable lens 7 has been described. However, such blurdetection section and blur correction unit may be provided to either oneof the camera body 4 and the interchangeable lens 7. Also, aconfiguration in which such blur detection section and blur correctionunit are not provided to either the camera body 4 or the interchangeablelens 7 may be employed (in such a configuration, a sequence regardingthe above-described blur correction may be eliminated).

—Configuration of Imaging Unit—

As shown in FIG. 2, the imaging unit 1 includes an imaging device 10 forconverting an object image into an electrical signal, a package 31 forholding the imaging device 10, and a phase difference detection unit 20for performing focus detection using phase difference detection.

The imaging device 10 is an interline type CCD image sensor, and, asshown in FIG. 3, includes a photoelectric conversion section 11 made ofa semiconductor material, vertical registers 12, transfer paths 13,masks 14, color filters 15, and microlenses 16.

The photoelectric conversion section 11 includes a substrate 11 a and aplurality of light receiving sections (also referred to as “pixels”) 11b arranged on the substrate 11 a.

The substrate 11 a is made of a Si (silicon) based substrate.Specifically, the substrate 11 a is made of a Si single crystalsubstrate or a SOI (silicon-on-insulator wafer). In particular, an SOIsubstrate has a sandwich structure of Si thin films and a SiO₂ thinfilm, and chemical reaction can be stopped at the SiO₂ film in etchingor like processing. Thus, in terms of performing stable substrateprocessing, it is advantageous to use an SOI substrate.

Each of the light receiving sections 11 b is made of a photodiode, andabsorbs light to generate electrical charges. The light receivingsections 11 b are provided in micro pixel regions each having a squareshape, arranged in matrix on the substrate 11 a (see FIG. 4).

The vertical register 12 is provided for each light receiving section 11b, and serves to temporarily store electrical charges stored in thelight receiving section 11 b. The electrical charges stored in the lightreceiving section 11 b are transferred to the vertical register 12. Theelectrical charges transferred to the vertical register 12 aretransferred to a horizontal register (not shown) via the transfer path13, and then, to an amplifier (not shown). The electrical chargestransferred to the amplifier are amplified and pulled out as anelectrical signal.

The mask 14 is provided so that the light receiving sections 11 b isexposed toward an object while the vertical register 12 and the transferpath 13 are covered by the mask 14, thereby preventing light fromentering the vertical register 12 and the transfer path 13.

The color filter 15 and the microlens 16 are provided in each micropixel region having a square shape to correspond to an associated one ofthe light receiving sections 11 b. Each of the color filters 15transmits only a specific color, and primary color filters orcomplementary color filters are used as the color filters 15. In thisembodiment, as shown in FIG. 4, so-called Bayer primary color filtersare used. That is, assuming that four color filters 15 arranged adjacentto one another in two rows and two columns (or in four pixel regions)are a repeat unit throughout the entire imaging device 10, two greencolor filters 15 g (i.e., color filters having a higher transmittance ina green visible light wavelength range than in the other color visiblelight wavelength ranges) are arranged in a diagonal direction, and a redcolor filter 15 r (i.e., a color filter having a higher transmittance ina red visible light wavelength range than in the other color visiblelight wavelength ranges) and a blue color filter 15 b (i.e., a colorfilter having a higher transmittance in a blue visible light wavelengthrange than in the other color visible light wavelength ranges) arearranged in another diagonal direction. When the entire set of the colorfilters 15 is viewed, every second color filter in the row and columndirections is the green color filter 15 g.

The microlenses 16 collect light to cause the light to enter the lightreceiving sections 11 b. The light receiving sections 11 b can beefficiently irradiated with light by the microlenses 16.

In the imaging device 10 configured in the above-described manner, lightcollected by the microlens 16 enters the color filters 15 r, 15 g and 15b. Then, only light having a corresponding color to each color filtertransmits through the color filter, and an associated one of the lightreceiving sections 11 b is irradiated with the light. Each of the lightreceiving sections 11 b absorbs light to generate electrical charges.The electrical charges generated by the light receiving sections 11 bare transferred to the amplifier via the vertical register 12 and thetransfer path 13, and are output as an electrical signal. That is, theamount of received light having a corresponding color to each colorfilter is obtained from each of the light receiving sections 11 b as anoutput.

Thus, the imaging device 10 performs photoelectric conversion at thelight receiving sections 11 b provided throughout the entire imagingplane, thereby converting an object image formed on an imaging planeinto an electrical signal.

In this case, a plurality of light transmitting portions 17 fortransmitting irradiation light are formed in the substrate 11 a. Thelight transmitting portions 17 are formed by cutting, polishing oretching an opposite surface (hereinafter also referred to as a “backsurface”) 11 c of the substrate 11 a to a surface thereof on which thelight receiving sections 11 b are provided to provide concave-shapedrecesses, and each of the light transmitting portions 17 has a smallerthickness than that of a part of the substrate 11 a located around eachof the light transmitting portions 17. More specifically, each of thelight transmitting portions 17 includes a recess-bottom surface 17 ahaving a smallest thickness and an inclined surfaces 17 b for connectingthe recess-bottom surface 17 a with the back surface 11 c.

Each of the light transmitting portions 17 in the substrate 11 a isformed to have a thickness which allows light to transmit through thelight transmitting portion 17, so that a part of irradiation light ontothe light transmitting portions 17 is not converted into electricalcharges and is transmitted through the photoelectric conversion section11. For example, by forming the substrate 11 a so that each of partsthereof located in the light transmitting portions 17 has a thickness of2-3 μm, about 50% of light having a longer wavelength than that of nearinfrared light can be caused to transmit through the light transmittingportions 17.

Each of the inclined surfaces 17 b is set to be at an angle at whichlight reflected by the inclined surfaces 17 b is not directed tocondenser lenses 21 a of the phase difference detection unit 20, whichwill be described later, when light is transmitted through the lighttransmitting portions 17. Thus, formation of a non-real image on a linesensor 24 a, which will be described later, is prevented.

Each of the light transmitting portions 17 serves as a reduced-thicknessportion, which transmits light entering the imaging device 10, i.e.,which allows light entering the imaging device 10 to pass therethrough.The term “passing” includes the concept of “transmitting” at least inthis specification.

The imaging device 10 configured in the above-described manner is heldin the package 31 (see FIG. 2). The package 31 serves as a holdingportion.

Specifically, the package 31 includes a flat bottom plate 31 a providedwith a frame 32, and upright walls 31 b provided in four directions. Theimaging device 10 is mounted on the frame 32 to be surrounded by theupright walls 31 b in four directions, and is electrically connected tothe frame 32 via bonding wires.

Moreover, a cover glass 33 is attached to ends of the upright walls 31 bof the package 31 to cover the imaging plane of the imaging device 10(on which the light receiving sections 11 b are provided). The imagingplane of the imaging device 10 is protected by the cover glass 33 fromdust and the like being attached thereto.

In this case, the same number of openings 31 c as the number of thelight transmitting portions 17 are formed in the bottom plate 31 a ofthe package 31 to pass through the bottom plate 31 a and be located atcorresponding positions to the positions of the light transmittingportions 17 of the imaging device 10. With the openings 31 c provided,light transmitted through the imaging device 10 reaches the phasedifference detection unit 20, which will be described later. Theopenings 31 c serves as light passing portions.

In the bottom plate 31 a of the package 31, the openings 31 c do nothave to be necessarily formed to pass through the bottom plate 31 a.That is, as long as light transmitted through the imaging device 10 canreach the phase difference detection unit 20, a configuration in whichtransparent portions or semi-transparent portions are formed in thebottom plate 31 a, or like configuration may be employed.

The phase difference detection unit 20 is provided in the back surface(an opposite surface to a surface facing an object) side of the imagingdevice 10 and receives light transmitted through the imaging device 10to perform phase difference detection. Specifically, the phasedifference detection unit 20 converts the received transmitted lightinto an electrical signal to be used for distance measurement. The phasedifference detection unit 20 serves as a phase difference detectionsection.

As shown in FIGS. 2 and 5, the phase difference detection unit 20includes a condenser lens unit 21, a mask member 22, a separator lensunit 23, a line sensor unit 24, a module frame 25 to which the condenserlens unit 21, the mask member 22, the separator lens unit 23 and theline sensor unit 24 are attached. The condenser lens unit 21, the maskmember 22, the separator lens unit 23 and the line sensor unit 24 arearranged in this order along the thickness direction of the imagingdevice 10 from the imaging device 10 side.

The plurality of condenser lenses 21 a integrated into a single unitform the condenser lens unit 21. The same number of the condenser lenses21 a as the number of the light transmitting portions 17 are provided.Each of the condenser lenses 21 a collects incident light. The condenserlens 21 a collects light transmitted through the imaging device 10 andspreading out, and guides the light to a separator lens 23 a of theseparator lens unit 23, which will be described later. Each of thecondenser lenses 21 a is formed so that an incident surface 21 b of thecondenser lens 21 a has a convex shape and a part thereof located closeto the incident surface 21 b has a circular column shape.

Since an incident angle of light entering each of the separator lenses23 a is reduced by providing the condenser lenses 21 a, an aberration ofthe separator lens 23 a can be reduced, and a distance between objectimages on a line sensor 24 a which will be described later can bereduced. As a result, the size of each of the separator lenses 23 a andthe line sensor 24 a can be reduced. Additionally, when a focus positionof an object image from the imaging optical system greatly diverges fromthe imaging unit 1 (specifically, greatly diverges from the imagingdevice 10 of the imaging unit 1), the contrast of the image isremarkably reduced. According to this embodiment, however, due to thesize-reduction effect of the condenser lenses 21 a and the separatorlenses 23 a, reduction in contrast can be prevented, so that a focusdetection range can be increased. If highly accurate phase differencedetection around a focus position is performed, or if the separatorlenses 23 a, the line sensors 24 a and the like are of sufficientdimensions, the condenser lens unit 21 does not have to be provided.

The mask member 22 is provided between the condenser lens unit 21 andthe separator lens unit 23. In the mask member 22, two mask openings 22a are formed in a part thereof corresponding to each of the separatorlenses 23 a. That is, the mask member 22 divides a lens surface of eachof the separator lenses 23 a into two areas, so that only the two areasare exposed toward the condenser lenses 21 a. More specifically, themask member 22 performs pupil division to divide light which has beencollected by the condenser lenses 21 a into two light beams and causesthe two light beams to enter the separator lens 23 a. The mask member 22can prevent harmful light from one of adjacent two of the separatorlenses 23 a from entering the other one of the adjacent two. Note thatthe mask member 22 does not have to be provided.

The separator lens unit 23 includes a plurality of separator lenses 23a. In other words, the separator lenses 23 a are integrated into asingle unit to form the separator lens unit 23. Like the condenserlenses 21 a, the same number of the separator lens 23 a as the number oflight transmitting portions 17 are provided. Each of the separatorlenses 23 a forms two identical object images on the line sensor 24 afrom two light beams which have passed through the mask member 22 andhas entered the separator lens 23 a.

The line sensor unit 24 includes a plurality of line sensors 24 a and amounting portion 24 b on which the line sensors 24 a are mounted. Likethe condenser lenses 21 a, the same number of the line sensors 24 a asthe number of the light transmitting portions 17 are provided. Each ofthe line sensors 24 a receives an image formed on an imaging plane andconverts the image into an electrical signal. That is, a distancebetween the two object images can be detected from an output of the linesensor 24 a, and a shift amount (defocus amount: Df amount) of a focusof an object image to be formed on the imaging device 10, and thedirection (defocus direction) in which the focus is shifted can beobtained based on the distance. (The Df amount, the defocus directionand the like will be hereinafter also referred to as “defocusinformation.”)

The condenser lens unit 21, the mask member 22, the separator lens unit23 and the line sensor unit 24, configured in the above-describedmanner, are provided in the module frame 25.

The module frame 25 is a member formed to have a frame shape, and anattaching section 25 a is provided on an inner circumference surface ofthe module frame 25 to inwardly protrude. A first attaching portion 25 band a second attaching portion 25 c are formed into a step-like shape ata part of the attaching section 25 a located closer to the imagingdevice 10. Moreover, a third attaching portion 25 d is formed at a partof the attaching section 25 a located at an opposite side to the imagingdevice 10.

The mask member 22 is attached to a side of the second attaching portion25 c of the module frame 25 located closer to the imaging device 10, andthe condenser lens unit 21 is attached to the first attaching portion 25b. As shown in FIGS. 2 and 5, the condenser lens unit 21 and the maskmember 22 are formed so that their edge portions fit in the module frame25 when the condenser lens unit 21 and the mask member 22 are attachedto the first attaching portion 25 b and the second attaching portion 25c. Thus, the positions of the condenser lens unit 21 and mask member 22are determined relative to the module frame 25.

The separator lens unit 23 is attached to a side of the third attachingportion 25 d of the module frame 25 located opposite to the imagingdevice 10. The third attaching portion 25 d is provided with positioningpins 25 e and direction reference pins 25 f each protruding at anopposite side to the condenser lens unit 21 side. The separator lensunit 23 is provided with positioning holes 23 b and direction referenceholes 23 c corresponding respectively to the positioning pins 25 e andthe direction reference pins 25 f. Respective diameters of thepositioning pins 25 e and the positioning holes 23 b are determined sothat the positioning pins 25 e closely fit in the positioning holes 23b. Respective diameters of the direction reference pins 25 f and thedirection reference holes 23 c are determined so that the directionreference pins 25 f loosely fit in the direction reference holes 23 c.That is, the attitude of the separator lens unit 23, such as thedirection in which the separator lens unit 23 is arranged when beingattached to the third attaching portion 25 d, is defined by insertingthe positioning pins 25 e and the direction reference pins 25 f of thethird attaching portion 25 d in the positioning holes 23 b and thedirection reference holes 23 c, and the position of the separator lensunit 23 is determined relative to the third attaching portion 25 d byproviding a close fit of the positioning pins 25 e with the positioningholes 23 b. Thus, when the attitude and position of the separator lensunit 23 are determined and then the separator lens unit 23 is attached,the lens surface of each of the separator lenses 23 a is directed towardthe condenser lens unit 21 and faces to an associated one of the maskopenings 22 a.

In the above-described manner, the condenser lens unit 21, the maskmember 22 and the separator lens unit 23 are attached while being heldin positions determined relative to the module frame 25. That is, thepositional relation of the condenser lens unit 21, the mask member 22and the separator lens unit 23 are determined by the module frame 25.

Then, the line sensor unit 24 is attached to a side of the module frame25 located closer to the back surface side of the separator lens unit 23(which is the opposite side to the condenser lens unit 21 side). In thiscase, the line sensor unit 24 is attached to the module frame 25 whilebeing held in a position which allows light transmitted through each ofthe separator lenses 23 a to enter an associated one of the line sensors24 a.

Thus, the condenser lens unit 21, the mask member 22, the separator lensunit 23 and the line sensor unit 24 are attached to the module frame 25,and thereby, the condenser lenses 21 a, the mask member 22, theseparator lenses 23 a and the line sensor 24 a are arranged to belocated at determined positions so that incident light to the condenserlenses 21 a is transmitted through the condenser lenses 21 a to enterthe separator lenses 23 a via the mask member 22, and then, the lighttransmitted through the separator lenses 23 a forms an image on each ofthe line sensors 24 a.

The imaging device 10 and the phase difference detection unit 20configured in the above-described manner are joined together.Specifically, the imaging device 10 and the phase difference detectionunit 20 are configured so that the openings 31 c of the package 31 inthe imaging device 10 closely fit the condenser lenses 21 a in the phasedifference detection unit 20. That is, with the condenser lenses 21 a inthe phase difference detection unit 20 inserted in the openings 31 c ofthe package 31 in the imaging device 10, the module frame 25 is bondedto the package 31. Thus, the respective positions of the imaging device10 and the phase difference detection unit 20 are determined, and then,the imaging device 10 and the phase difference detection unit 20 arejoined together while being held in the positions. As described above,the condenser lenses 21 a, the separator lenses 23 a and the linesensors 24 a are integrated into a single unit, and then are attached asa signal unit to the package 31.

The imaging device 10 and the phase difference detection unit 20 may beconfigured so that all of the openings 31 c closely fit the condenserlenses 21 a. Alternatively, the imaging device 10 and the phasedifference detection unit 20 may be also configured so that only some ofthe openings 31 c closely fit associated ones of the condenser lenses 21a, and the rest of the openings 31 c loosely fit associated ones of thecondenser lenses 21 a. In the latter case, the imaging device 10 and thephase difference detection unit 20 are preferably configured so that oneof the condenser lenses 21 a and one of the openings 31 c locatedclosest to the center of the imaging plane closely fit each other todetermine positions in the imaging plane, and furthermore, one of thecondenser lenses 21 a and one of the openings 31 c located most distantfrom the center of the imaging plane closely fit each other to determinecircumferential positions (rotation angles) of the condenser lens 21 aand the opening 31 c which are located at the center of the imagingplane.

As a result of joining the imaging device 10 and the phase differencedetection unit 20 together, the condenser lens 21 a, the pair of themask openings 22 a of the mask member 22, the separator lens 23 a andthe line sensor 24 a are arranged in the back surface side of thesubstrate 11 b to correspond to each of the light transmitting portions17.

As described above, relative to the imaging device 10 configured totransmit light therethrough, the openings 31 c are formed in the bottomplate 31 a of the package 31 for housing the imaging device 10, andthereby, light transmitted through the imaging device 10 is easilycaused to reach the back surface side of the package 31. Also, the phasedifference detection unit 20 is arranged in the back surface side of thepackage 31, and thus, a configuration where light transmitted throughthe imaging device 10 is received at the phase difference detection unit20 can be easily realized.

As long as light transmitted through the imaging device 10 can passthrough the openings 31 c formed in the bottom plate 31 a of the package31 to the back surface side of the package 31, any configuration can beemployed for the openings 31 c. However, by forming the openings 31 c asthrough holes, light transmitted through the imaging device 10 can becaused to reach the back surface side of the package 31 withoutattenuating light transmitted through the imaging device 10.

With the openings 31 c provided to closely fit the condenser lenses 21a, positioning of the phase difference detection unit 20 relative to theimaging device 10 can be performed using the openings 31 c. If thecondenser lenses 21 a are not provided, the separator lenses 23 a areconfigured to fit the openings 31 c. Thus, positioning of the phasedifference detection unit 20 relative to the imaging device 10 can beperformed in the same manner.

In addition, the condenser lenses 21 a can be provided to pass throughthe bottom plate 31 a of the package 31 and reach a close point to thesubstrate 11 a. Thus, the imaging unit 1 can be configured as a compactsize imaging unit.

The operation of the imaging unit 1 configured in the above-describedmanner will be described hereinafter.

When light enters the imaging unit 1 from an object, the light istransmitted through the cover glass 33 and enters the imaging device 10.The light is collected by the microlenses 16 of the imaging device 10,and then, is transmitted through the color filters 15, so that onlylight of a specific color reaches the light receiving sections 11 b. Thelight receiving sections 11 b absorbs light to generate electricalcharges. Generated electrical charges are transferred to the amplifiervia the vertical register 12 and the transfer path 13, and are output asan electrical signal. Thus, each of the light receiving sections 11 bconverts light into an electrical signal throughout the entire imagingplane, and thereby, the imaging device 10 converts an object imageformed on the imaging plane into an electrical signal for generating animage signal.

In the light transmitting portions 17, a part of irradiation light tothe imaging device 10 is transmitted through the imaging device 10. Thelight transmitted through the imaging device 10 enters the condenserlenses 21 a which are provided to closely fit the openings 31 c of thepackage 31. The light transmitted through each of the condenser lenses21 a and collected is divided into two light beams, when passing througheach pair of mask openings 22 a formed in the mask member 22, and then,enters each of the separator lenses 23 a. Light subjected to pupildivision is transmitted through the separator lens 23 a, and identicalobject images are formed at two positions on the line sensor 24 a. Theline sensor 24 a performs photoelectric conversion to generate anelectrical signal from the object images and outputs the electricalsignal.

In this case, the electrical signal output from the imaging device 10 isinput to the body microcomputer 50 via the imaging unit control section52. The body microcomputer 50 obtains positional information of each ofthe light receiving sections 11 b and output data corresponding to theamount of light received by the light receiving section 11 b from theentire imaging plane of the imaging device 10, thereby obtaining anobject image formed on the image plane as an electrical signal.

In this case, in the light receiving sections 11 b, even when the samelight amount is received, the amount of accumulated charges aredifferent among different lights having different wavelengths. Thus,outputs from the light receiving sections 11 b of the imaging device 10are corrected according to the types of the color filters 15 r, 15 g and15 b provided to the light receiving sections 11 b. For example, acorrection amount for each pixel is determined so that, when each of a Rpixel 11 b to which the red color filter 15 r is provided, a G pixel 11b to which the green color filter 15 g is provided, and a B pixel 11 bto which the blue color filter 15 b is provided receives the same amountof light corresponding to the color of each color filter, respectiveoutputs of the R pixel 11 b, the G pixel 11 b and the B pixel 11 bbecome at the same level.

In this embodiment, the light transmitting portions 17 are provided inthe substrate 11 a, and thus, the photoelectric conversion efficiency isreduced in the light transmitting portions 17, compared to the otherportions. That is, even when the pixels 11 b receive the same lightamount, the amount of accumulated charges is smaller in ones of thepixels 11 b provided in positions corresponding to the lighttransmitting portions 17 than in the other ones of the pixels 11 bprovided in positions corresponding to the other portions. Accordingly,when the same image processing as image processing for output data fromthe pixels 11 b provided in positions corresponding to the otherportions is performed to output data from the pixels 11 b provided inpositions corresponding to the light transmitting portions 17, parts ofan image corresponding to the light transmitting portions 17 might notbe able to be properly shot (for example, shooting image is dark).Therefore, an output of each of the pixels 11 b in the lighttransmitting portions 17 is corrected to eliminate or reduce theinfluence of the light transmitting portions 17 (for example, byamplifying an output of each of the pixels 11 b in the lighttransmitting portions 17 or like method).

Reduction in output varies depending on the wavelength of light. Thatis, as the wavelength increases, the transmittance of the substrate 11 aincreases. Thus, depending on the types of the color filters 15 r, 15 gand 15 b, the amount of light transmitted through the substrate 11 adiffers. Therefore, when correction to eliminate or reduce the influenceof the light transmitting portions 17 on each of the pixels 11 bcorresponding to the light transmitting portions 17 is performed, thecorrection amount is changed according to the wavelength of lightreceived by each of the pixels 11 b. That is, for each of the pixels 11b corresponding to the light transmitting portions 17, the correctionamount is increased as the wavelength of light received by the pixel 11b increases.

As described above, in each of the pixels 11 b, the correction amountfor eliminating or reducing the difference of the amount of accumulatedcharges depending on the types of color of received light is determined.In addition to the correction to eliminate or reduce the difference ofthe amount of accumulated charges depending on the types of color ofreceived light, correction to eliminate or reduce the influence of thelight transmitting portions 17 is performed. That is, the correctionamount for eliminating or reducing the influence of the lighttransmitting portions 17 is a difference between the correction amountfor each of the pixels 11 b corresponding to the light transmittingportions 17 and the correction amount for the pixels 11 b whichcorrespond to the other portions than the light transmitting portions 17and receive light having the same color. In this embodiment, differentcorrection amounts are determined for different colors, based on thefollowing relationship. Thus, a stable image output can be obtained.

Rk>Gk>Bk  [Expression 1]

where Rk is: a difference obtained by deducting the correction amountfor R pixels in the other portions than the light transmitting portions17 from the correction amount for R pixels in the light transmittingportions 17, Gk is: a difference obtained by deducting the correctionamount for G pixels in the other portions than the light transmittingportions 17 from the correction amount for G pixels in the lighttransmitting portions 17, and Bk is: a difference obtained by deductingthe correction amount for B pixels in the other portions than the lighttransmitting portions 17 from the correction amount for B pixels in thelight transmitting portions 17.

Specifically, since the transmittance of red light having the largestwavelength is the highest of the transmittances of red, green and bluelights, the difference in the correction amount for red pixels is thelargest. Also, since the transmittance of blue light having the smallestwavelength is the lowest of the transmittances of red, green and bluelights, the difference in the correction amount for blue pixels is thesmallest.

That is, the correction amount of an output of each of the pixels 11 bin the imaging device 10 is determined based on whether or not the pixel11 b is provided on a position corresponding to the light transmittingportion 17, and the type of color of the color filter 15 correspondingto the pixel 11 b. For example, the correction amount of an output ofeach of the pixels 11 b is determined so that the white balance and/orintensity is equal for an image displayed by an output from the lighttransmitting portion 17 and an image displayed by an output from someother portion than the light transmitting portion 17.

The body microcomputer 50 corrects output data from the light receivingsections 11 b in the above-described manner, and then, generates, basedon the output data, an image signal including positional information,color information and intensity information in each of the lightreceiving sections, i.e., the pixels 11 b. Thus, an image signal of anobject image formed on the imaging plane of the imaging device 10 isobtained.

By correcting an output from the imaging device 10 in theabove-described manner, an object image can be properly shot even by theimaging device 10 provided with the light transmitting portions 17.

An electrical signal output from the line sensor unit 24 is also inputto the body microcomputer 50. The body microcomputer 50 can obtain adistance between two object images formed on the line sensor 24 a, basedon the output from the line sensor unit 24, and then, can detect anin-focus state of an object image formed on the imaging device 10 fromthe obtained distance. For example, when an object image is transmittedthrough an imaging lens and is correctly formed on the imaging device 10(in focus), the two object images formed on the line sensor 24 a arelocated at predetermined reference positions with a predeterminedreference distance therebetween. In contrast, when an object image isformed before the imaging device 10 in the direction along the opticalaxis (front focus), the distance between the two object images issmaller than the reference distance when the object image is in focus.When an object image is formed behind the imaging device 10 in thedirection along the optical axis (back focus), the distance between thetwo object images is larger than the reference distance when the objectimage is in focus. That is, an output from the line sensor 24 a isamplified, and then, an operation by the arithmetic circuit obtainsinformation regarding whether or not an object image has been broughtinto focus, whether the object is in front focus or back focus, and theDf amount.

According to this embodiment, three light transmitting portions 17 areformed in the imaging device 10, and in the back surface side of each ofthe light transmitting portions 17, the condenser lens 21 a of the phasedifference detection unit 20, a pair of mask openings 22 a of the maskmember 22, the separator lens 23 a and the line sensor 24 a are providedto be arranged along the optical axis. That is, the imaging unit 1(specifically, the imaging device 10 and the phase difference detectionunit 20) includes three areas (hereinafter also referred to as “phasedifference areas”) for detection of a phase difference, in which thecondenser lens 21 a, a pair of the mask openings 22 a of the mask member22, the separator lens 23 a and the line sensor 24 a are arranged alongthe optical axis.

According to this embodiment, each of the light transmitting portions 17is formed in the substrate 11 a to have a smaller thickness than that ofa part of the substrate 11 a located around the light transmittingportion 17. However, the present invention is not limited thereto. Forexample, the thickness of the entire substrate 11 a may be determined sothat a part of irradiation light onto the substrate 11 a in a sufficientamount is transmitted through the substrate 11 a to reach the phasedifference detection unit 20 provided in the back surface side of thesubstrate 11 a. In such a case, the entire substrate 11 a serves as thelight transmitting portion 17.

Also, according to this embodiment, three light transmitting portions 17are formed in the substrate 11 a, and three phase difference areas areprovided. However, the present invention is not limited thereto. Thenumber of each of those components is not limited to three, but may beany number. For example, as shown in FIG. 6, nine light transmittingportions 17 may be formed in the substrate 11 a, and accordingly, ninesets of the condenser lens 21 a, the separator lens 23 a and the linesensor 24 a may be provided, thereby providing nine phase differenceareas.

Furthermore, the imaging device 10 is not limited to a CCD image sensorbut, as shown in FIG. 7, may be a CMOS image sensor.

An imaging device 210 is a CMOS image sensor, and includes aphotoelectric conversion section 211 made of a semiconductor material,transistors 212, signal lines 213, masks 214, color filters 215, andmicrolenses 216.

The photoelectric conversion section 211 includes a substrate 211 a, andlight receiving sections 211 b each being comprised of a photodiode. Thetransistor 212 is provided for each of the light receiving sections 211b. Electrical charges accumulated in the light receiving sections 211 bare amplified by the transistors 212 and are output to the outside viathe signal lines 213. Respective configurations of the masks 214, thecolor filters 215 and the microlenses 216 are the same as those of themask 14, the color filter 15 and the microlens 16.

As in the CCD image sensor, the light transmitting portions 17 fortransmitting irradiation light are formed in the substrate 211 a. Thelight transmitting portions 17 are formed by cutting, polishing oretching an opposite surface (hereinafter also referred to as a “backsurface”) 211 c of the substrate 211 a to a surface thereof on which thelight receiving sections 211 b are provided to provide concave-shapedrecesses, and each of the light transmitting portions 17 is formed tohave a smaller thickness than that of a part of the substrate 11 alocated around each of the light transmitting portions 17.

In the CMOS image sensor, an amplification rate of the transistor 212can be determined for each light receiving section 211 b. Therefore, bydetermining the amplification rate of each transistor 212 based onwhether or not each light receiving section 11 b is located at aposition corresponding to the light transmitting portion 17 and the typeof color of the color filter 15 corresponding to the light receivingsection 11 b, parts of an image corresponding to the light transmittingportions 17 can be prevented from being not properly shot.

The configuration of an imaging device through which light passes is notlimited to the configuration in which the light transmitting portions 17are provided in the manner described above. As long as light passes (oris transmitted, as described above) through the imaging device, anyconfiguration can be employed. For example, as shown in FIG. 8, animaging device 310 including light passing portions 318 each of whichincludes a plurality of through holes 318 a formed in a substrate 311 amay be employed.

Each of the through holes 318 a is formed to pass through the substrate311 a in the thickness direction of the substrate 311 a. Specifically,regarding pixel regions formed on the substrate 311 a to be arranged inmatrix, when it is assumed that four pixel regions located in twoadjacent columns and two adjacent rows are as a single unit, the lightreceiving sections 11 b are provided in three of the four pixel regions,and the through hole 318 a is formed in the other one of the fourpixels.

In the three pixel regions of the four pixel regions in which the lightreceiving sections 11 b are provided, three color filters 15 r, 15 g and15 b corresponding to respective colors of the three light receivingsections 11 b are provided. Specifically, a green color filter 15 g isprovided in the light receiving section 11 b located in a diagonalposition to the through hole 318 a, a red color filter 15 r is providedin one of the light receiving sections 11 b located adjacent to thethrough hole 318 a, and a blue color filter 15 b is provided in theother one of the light receiving sections 11 b located adjacent to thethrough hole 318 a. No color filter is provided in the pixel regioncorresponding to the through hole 318 a.

In the imaging device 10, a pixel corresponding to each through hole 318a is interpolated using outputs of the light receiving sections 11 blocated adjacent to the through hole 318 a. Specifically, interpolation(standard interpolation) of a signal of the pixel corresponding to thethrough hole 318 a is performed using an average value of outputs of thefour light receiving sections 11 b each of which is located diagonallyadjacent to the through hole 318 a in the pixel regions and in which thegreen color filters 15 g are provided. Alternatively, in the four lightreceiving sections 11 b each of which is located diagonally adjacent tothe through hole 318 a in the pixel regions and in which the green colorfilters 15 g are provided, change in output of one pair of the lightreceiving sections 11 b located adjacent to each other in one diagonaldirection is compared to change in output of the other pair of the lightreceiving sections 11 b located adjacent to each other in the otherdiagonal direction, and then, interpolation (slope interpolation) of asignal of a pixel corresponding to the through hole 318 a is performedusing an average value of outputs of the pair of the light receivingsections 11 b, located diagonally adjacent, whose change in output islarger, or an average value of outputs of the pair of the lightreceiving sections 11 b, located diagonally adjacent, whose change inoutput is smaller. Assume that a pixel desired to be interpolated is anedge of a focus object. If interpolation is performed using the pair ofthe light receiving sections 11 b whose change in output is larger, theedge is undesirably caused to be loose. Therefore, the smaller change isused when each of the changes are equal to or larger than apredetermined threshold, and the larger change is used when each of thechanges is smaller than the predetermine threshold so that as smallchange rate (slope) as possible is employed.

Then, after performing the interpolation of output data of the lightreceiving sections 11 b corresponding to the through holes 318 a,intensity information and color information for the pixel correspondingto each of the light receiving sections 11 b are obtained using outputdata of each of the light receiving sections 11 b and, furthermore,predetermined image processing or image synthesis is performed togenerate an image signal.

Thus, it is possible to prevent parts of an image at the light passingportions 318 from becoming dark.

The imaging device 310 configured in the above-described manner cancause incident light to pass therethrough via the plurality of thethrough holes 318 a.

As described above, also by providing, instead of the light transmittingportions 17, the light passing portions 318 made of the through holes318 a in the substrate 311 a, the imaging device 310 through which lightpasses can be configured. Moreover, the imaging device 310 is configuredso that light from the plurality of through holes 318 a enters a set ofthe condenser lens 21 a, the separator lens 23 a and the line sensor 24a, and thus, advantageously, the size of one set of the condenser lens21 a, the separator lens 23 a and the line sensor 24 a is not restrictedby the size of pixels. That is, advantageously, the size of one set ofthe condenser lens 21 a, the separator lens 23 a and the line sensor 24a does not cause any problem in increasing the resolution of the imagingdevice 310 by reducing the size of pixels.

The light passing portions 318 may be provided only in each part of thesubstrate 311 a corresponding to the condenser lenses 21 a and theseparator lens 23 a of the phase difference detection unit 20, or may beprovided throughout the entire substrate 311 a.

Furthermore, the phase difference detection unit 20 is not limited tothe above-described configuration. For example, as long as aconfiguration in which the positions of the condenser lenses 21 a andthe separator lens 23 a are determined relative to the lighttransmitting portions 17 of the imaging device 10 is provided, thecondenser lenses 21 a do not necessarily have to closely fit theopenings 31 c of the package 31. Also, a configuration which does notinclude a condenser lens may be employed. Alternatively, a configurationin which a condenser lens and a separator lens are integrated into asingle unit may be employed.

As another example, as shown in FIGS. 9 and 10, a phase differencedetection unit 420 in which a condenser lens unit 421, a mask member422, a separator lens unit 423 and a line sensor unit 424 are providedso as to be arranged in parallel to the imaging plane of the imagingdevice 10 in the back surface side of the imaging device 10 may beemployed.

Specifically, the condenser lens unit 421 is configured so that aplurality of condenser lenses 421 a are integrated into a single unit,and includes an incident surface 421 b, a reflection surface 421 c andan output surface 421 d. That is, in the condenser lens unit 421, lightcollected by the condenser lenses 421 a is reflected by the reflectionsurface 421 c at an angle of about 90 degrees, and is output from theoutput surface 421 d. As a result, the light which has been transmittedthrough the imaging device 10 and has entered the condenser lens unit421 is bent substantially at a right angle, and output from the outputsurface 421 d to be directed to a separator lens 423 a of a separatorlens unit 423. The light which has entered the separator lens 423 a istransmitted through the separator lens 423 a, and forms an image on theline sensor 424 a.

The condenser lens unit 421, the mask member 422, the separator lensunit 423 and the line sensor unit 424, configured in the above-describedmanner, are provided within the module frame 425.

The module frame 425 is formed to have a box shape, and a step portion425 a for attaching the condenser lens unit 421 is provided in themodule frame 425. The condenser lens unit 421 is attached to the stepportion 425 a so that the condenser lenses 421 a face outward from themodule frame 425.

Moreover, in the module frame 425, an attachment wall potion 425 b forattaching the mask member 422 and the separator lens unit 423 isprovided so as to upwardly extend at a part facing the output surface421 d of the condenser lens unit 421. An opening 425 c is formed in theattachment wall potion 425 b.

The mask member 422 is attached to a side of the attachment wall potion425 b located closer the condenser lens unit 421. The separator lensunit 423 is attached to a side of the attachment wall potion 425 blocated opposite to the condenser lens unit 421.

Thus, the optical path of light which has passed through the imagingdevice 10 is bent in the back surface side of the imaging device 10, andthus, the condenser lens unit 421, the mask member 422, the separatorlens unit 423, the line sensor unit 424 and the like can be arranged notin the thickness direction of the imaging device 10 but in parallel tothe imaging plane of the imaging device 10. Therefore, a dimension ofthe imaging unit 401 in the thickness direction of the imaging device 10can be reduced. That is, an imaging unit 401 can be formed as a compactsize imaging unit 401.

As described above, as long as light which has passed through theimaging device 10 can be received in the back surface side of theimaging device 10 and then phase difference detection can be performed,a phase difference detection unit having any configuration can beemployed.

—Operation of Camera—

The camera 100 configured in the above-described manner has variousshooting modes and functions. The various shooting modes and functionsof the camera 100, and the operation thereof at the time of each of themodes and functions will be described hereinafter.

—AF Function—

When the release button 40 b is pressed halfway down, the camera 100performs AF to focus. To perform AF, the camera 100 has three autofocusfunctions, i.e., phase difference detection AF, contrast detection AFand hybrid AF. A user can select one of the three autofocus functions tobe used by operating the AF setting switch 40 c provided to the camerabody 4.

Assuming that a camera system is in a normal shooting mode, the shootingoperation of the camera system using each of the autofocus functionswill be described hereinafter. The “normal shooting mode” is not aduring-exposure AF shooting mode, a macro shooting mode, or a continuousshooting mode, which will be described later, but a most basic shootingmode of the camera 100 for normal shooting.

(Phase Difference Detection AF)

First, the shooting operation of the camera system using phasedifference detection AF will be described with reference of FIGS. 11 and12.

When the power switch 40 a is turned on (Step Sa1), communicationbetween the camera body 4 and the interchangeable lens 7 is performed(Step Sa2). Specifically, power is supplied to the body microcomputer 50and each of other units in the camera body 4 to start up the bodymicrocomputer 50. At the same time, power is supplied to the lensmicrocomputer 80 and each of other units in the interchangeable lens 7via the electric contact pieces 41 a and 71 a to start up the lensmicrocomputer 80. The body microcomputer 50 and the lens microcomputer80 are programmed to transmit/receive information to/from each other atstart-up time. For example, lens information for the interchangeablelens 7 is transmitted from the memory section of the lens microcomputer80 to the body microcomputer 50, and then is stored in the memorysection of the body microcomputer 50.

Subsequently, the body microcomputer 50 positions the focus lens group72 at a predetermined reference position which has been determined inadvance by the lens microcomputer 80 (Step Sa3), and also puts theshutter unit 42 into an open state (Step Sa4) in parallel with Step Sa3.Then, the process proceeds to Step Sa5, and the body microcomputer 50remains in a standby state until the release button 40 b is pressedhalfway down by the user.

Thus, light which has been transmitted through the interchangeable lens7 and has entered the camera body 4 passes through the shutter unit 42,is transmitted through the OLPF 43 serving also as an IR cutter, andthen enters the imaging unit 1. An object image formed in the imagingunit 1 is displayed at the image display section 44, so that the usercan observe an erected image of an object through the image displaysection 44. Specifically, the body microcomputer 50 reads an electricalsignal from the imaging device 10 via the imaging unit control section52 at constant intervals, and performs predetermined image processing tothe electrical signal that has been read. Then, the body microcomputer50 generates an image signal, and controls the image display controlsection 55 to cause the image display section 44 to display a live viewimage.

A part of the light which has entered the imaging unit 1 is transmittedthrough the light transmitting portions 17 of the imaging device 10, andenters the phase difference detection unit 20.

In this case, when the release button 40 b is pressed halfway down(i.e., S1 switch, which is not shown in the drawings, is turned on) bythe user (Step Sa5), the body microcomputer 50 amplifies an output fromthe line sensor 24 a of the phase difference detection unit 20, and thenan operation by the arithmetic circuit obtains information regardingwhether or not an object image has been brought into focus, whether theobject is in front focus or back focus, and the Df amount (Step Sa6).

Thereafter, the body microcomputer 50 drives the focus lens group 72 viathe lens microcomputer 80 in the defocus direction by the Df amountobtained in Step Sa6 (Step Sa7).

In this case, the phase difference detection unit 20 of this embodimentincludes three sets of the condenser lens 21 a, the mask openings 22 a,separator lens 23 a, and the line sensor 24 a, i.e., has three phasedifference areas at which phase difference detection is performed. Inphase difference detection in phase difference detection AF or hybridAF, the focus lens group 72 is driven based on an output of the linesensor 24 a of one of the sets corresponding to a distance measurementpoint arbitrarily selected by the user.

Alternatively, an automatic optimization algorithm may be installed inthe body microcomputer 50 beforehand to select one of the distancemeasurement points located closest to the camera and drive the focuslens group 72. Thus, the rate of the occurrence of focusing on thebackground of an object instead of the object can be reduced.

Application of this selection of the distance measurement point is notlimited to phase difference detection AF. As long as the focus lensgroup 72 is driven using the phase difference detection unit 2, thisselection can be employed in AF using any method.

Then, whether or not an object image has been brought into focus isdetermined (Step Sa8). Specifically, if the Df amount obtained based onthe output of the line sensor 24 a is equal to or smaller than apredetermined value, it is determined that an object image has beenbrought into focus (YES), and then, the process proceeds to Step Sa11.If the Df amount obtained based on the output of the line sensor 24 a islarger than the predetermined value, it is determined that an object hasnot been brought into focus (NO), the process returns to Step Sa6, andSteps Sa6-Sa8 are repeated.

In the above-described manner, detection of an in-focus state anddriving of the focus lens group 72 are repeated and, when the Df amountis equal to or smaller than the predetermined value, it is determinedthat an object image has been brought into focus, and driving of thefocus lens group 72 is halted.

In parallel with phase difference detection AF in Steps Sa6-Sa8,photometry is performed (Step Sa9), and also image blur detection isstarted (Step Sa10).

Specifically, in Step Sa9, the amount of light entering the imagingdevice 10 is measured by the imaging device 10. That is, in thisembodiment, the above-described phase difference detection AF isperformed using light which has entered the imaging device 10 and hasbeen transmitted through the imaging device 10, and thus, photometry canbe performed using the imaging device 10 in parallel with theabove-described phase difference detection AF.

More specifically, the body microcomputer 50 retrieves an electricalsignal from the imaging device 10 via the imaging unit control section52, and measures the intensity of object light based on the electricalsignal, thereby performing photometry. According to a predeterminedalgorithm, the body microcomputer 50 determines, from a result ofphotometry, a shutter speed and an aperture value, which correspond to ashooting mode at the time of exposure.

When photometry is terminated in Step Sa9, image blur detection isstarted in Step Sa10. Step Sa9 and Step Sa10 may be performed inparallel.

When the release button 40 b is pressed halfway down by the user,various pieces of information for shooting are displayed as well as ashooting image at the image display section 44, and thus, the user canconfirm each piece of information through the image display section 44.

In Step Sa11, the body microcomputer 50 remains in a standby state untilthe release button 40 b is pressed all the way down (i.e., a S2 switch,which is not shown in the drawings, is turned on) by the user. When therelease button 40 b is pressed all the way down by the user, the bodymicrocomputer 50 temporarily puts the shutter unit 42 into a close state(Step Sa12). Then, while the shutter unit 42 is kept in a close state,electrical charges stored in the light receiving sections 11 b of theimaging device 10 are transferred for exposure, which will be describedlater.

Thereafter, the body microcomputer 50 starts correction of an image blurbased on communication information between the camera body 4 and theinterchangeable lens 7 or any information specified by the user (StepSa13). Specifically, the blur correction lens driving section 74 a inthe interchangeable lens 7 is driven based on information of the blurdetection section 56 in the camera body 4. According to the intention ofthe user, any one of (i) use of the blur detection section 84 and theblur correction lens driving section 74 a in the interchangeable lens 7,(ii) use of the blur detection section 56 and the blur correction unit45 in the camera body 4, and (iii) use of the blur detection section 84in the interchangeable lens 7 and the blur correction unit 45 in thecamera body 4 can be selected.

By starting driving of the image blur correction sections at a time whenthe release button 40 b is pressed halfway down, the movement of anobject desired to be in focus is reduced, and thus, phase differencedetection AF can be performed with higher accuracy.

In parallel with starting of image blur correction, the bodymicrocomputer 50 stops down the aperture section 73 via the lensmicrocomputer 80 so as to attain an aperture value calculated based on aresult of photometry in Step Sa9 (Step Sa14).

Thus, when the image blur correction is started and the apertureoperation is terminated, the body microcomputer 50 puts the shutter unit42 into an open state based on the shutter speed obtained from theresult of photometry in Step Sa9 (Step Sa15). In the above-describedmanner, the shutter unit 42 is put into an open state, so that lightfrom the object enters the imaging device 10, and electrical charges arestored in the imaging device 10 only for a predetermined time (StepSa16).

The body microcomputer 50 puts the shutter unit 42 into a close statebased on the shutter speed, to terminate exposure (Step Sa17). After thetermination of the exposure, in the body microcomputer 50, image data isread out from the imaging unit 1 via the imaging unit control section 52and then, after performing predetermined image processing to the imagedata, the image data is output to the image display control section 55via the image reading/recording section 53. Thus, a shooting image isdisplayed at the image display section 44. The body microcomputer 50stores the image data in the image storage section 58 via the imagerecording control section 54 as necessary.

Thereafter, the body microcomputer 50 terminates image blur correction(Step Sa18), and releases the aperture section 73 (Step Sa19). Then, thebody microcomputer 50 puts the shutter unit 42 into an open state (StepSa20).

When a reset operation is terminated, the lens microcomputer 80 notifiesthe body microcomputer 50 of the termination of the reset operation. Thebody microcomputer 50 waits to receive reset termination informationfrom the lens microcomputer 80 and also a series of processings afterexposure to be terminated. Thereafter, the body microcomputer 50confirms that the release button 40 b is not in a pressed state, andterminates a shooting sequence. Then, the process returns to Step Sa5,and the body microcomputer 50 remains in a standby state until therelease button 40 b is pressed halfway down.

When the power switch 40 a is turned off (Step Sa21), the bodymicrocomputer 50 moves the focus lens group 72 to a predeterminedreference position which has been determined in advance (Step Sa22), andputs the shutter unit 42 into a close state (Step Sa23). Then,respective operations of the body microcomputer 50 and other units inthe camera body 4, and the lens microcomputer 80 and other units in theinterchangeable lens 7 are halted.

As described above, in the shooting operation of the camera system usingphase difference detection AF, photometry is performed by the imagingdevice 10 in parallel with autofocusing based on the phase differencedetection unit 20. Specifically, the phase difference detection unit 20receives light transmitted through the imaging device 10 to obtaindefocus information, and thus, whenever the phase difference detectionunit 20 obtains defocus information, the imaging device 10 is irradiatedwith light from an object. Therefore, photometry is performed usinglight transmitted through the imaging device 10 in autofocusing. Bydoing so, a photometry sensor does not have to be additionally provided,and photometry can be performed before the release button 40 b ispressed all the way down, so that a time (hereinafter also referred toas a “release time lag”) from a time point when the release button 40 bis pressed all the way down to a time point when exposure is terminatedcan be reduced.

Moreover, even in a configuration in which photometry is performedbefore the release button 40 b is pressed all the way down, byperforming photometry in parallel with autofocusing, increase inprocessing time after the release button 40 b is pressed halfway downcan be prevented. In such a case, a mirror for guiding light from anobject to a photometry sensor or a phase difference detection unit doesnot have to be provided.

Conventionally, a part of light from an object to an imaging apparatusis directed to a phase difference detection unit provided outside theimaging apparatus by a mirror or the like. In contrast, according tothis embodiment, an in-focus state can be detected by the phasedifference detection unit 20 using light guided to the imaging unit 1 asit is, and thus, the in-focus state can be detected with very highaccuracy.

(Contrast Detection AF)

Next, the shooting operation of the camera system using contrastdetection AF will be described with reference to FIG. 13.

When the power switch 40 a is turned on (Step Sb1), communicationbetween the camera body 4 and the interchangeable lens 7 is performed(Step Sb2), the focus lens group 72 is positioned at a predeterminedreference position (Step Sb3), the shutter unit 42 is put into an openstate (Step Sb4) in parallel with Step Sb3, and then, the bodymicrocomputer 50 remains in a standby state until the release button 40b is pressed halfway down (Step Sb5). The above-described steps are thesame as Steps Sa1-Sa5.

When the release button 40 b is pressed halfway down by the user (StepSb5), the body microcomputer 50 drives the focus lens group 72 via thelens microcomputer 80 (Step Sb6). Specifically, the body microcomputer50 drives the focus lens group 72 so that a focal point of an objectimage is moved in a predetermined direction (e.g., toward an object)along the optical axis.

Then, the body microcomputer 50 obtains a contrast value for the objectimage, based on an output from the imaging device 10 received by thebody microcomputer 50 via the imaging unit control section 52, todetermine whether or not the contrast value is reduced (Step Sb7). Ifthe contrast value is reduced (YES), the process proceeds to Step Sb8.If the contrast value is increased (NO), the process proceeds to StepSb9.

Reduction in contrast value means that the focus lens group 72 is drivenin an opposite direction to the direction in which the object image isbrought into focus. Therefore, when the contrast value is reduced, thefocus lens group 72 is reversely driven so that the focal point of theobject image is moved in an opposite direction to the predetermineddirection (e.g., toward the opposite side to the object) along theoptical axis (Step Sb8). Thereafter, whether or not a contrast peak hasbeen detected is determined (Step Sb10). If the contrast peak has notbeen detected (NO), reverse driving of the focus lens group 72 (StepSb8) is repeated. If the contrast peak has been detected (YES), reversedriving of the focus lens group 72 is halted, and the focus lens group72 is moved to a position where the contrast value has reached the peak.Then, the process proceeds to Step Sa11.

On the other hand, when the focus lens group 72 is driven in Step Sb6and the contrast value is increased, the focus lens group 72 is drivenin the direction in which the object image is brought into focus.Therefore, driving of the focus lens group 72 is continued (Step Sb9),and whether or not a peak of the contrast value has been detected isdetermined (Step Sb10). If the contrast peak has not been detected (NO),driving of the focus lens group 72 (Step Sb9) is repeated. If thecontrast peak has been detected (YES), driving of the focus lens group72 is halted, and the focus lens group 72 is moved to a position wherethe contrast value has reached the peak. Then, the process proceeds toStep Sa11.

As has been described, in the contrast detection method, the focus lensgroup 72 is tentatively driven (Step Sb6). Then, if the contrast valueis reduced, the focus lens group 72 is reversely driven to search forthe peak of the contrast value (Steps Sb8 and Sb10). If the contrastvalue is increased, driving of the focus lens group 72 is continued tosearch for the peak of the contrast value (Steps Sb9 and Sb10).

In parallel with this contrast detection AF (Steps Sb6-Sb10), photometryis performed (Step Sb11), and also image blur detection is started (StepSb12). Steps Sb11 and Sb12 are the same as Step Sa9 and Step Sa11) inphase difference detection AF.

In Step Sa11, the body microcomputer 50 remains in a standby state untilthe release button 40 b is pressed all the way down by the user. A flowof steps after the release button 40 b is pressed all the way down isthe same as that of phase difference detection AF.

In this contrast detection AF, a contrast peak can be directly obtained,and thus, as opposed to phase difference detection AF, variouscorrection operations such as release back correction (for correcting anout-of-focus state due to the degree of aperture) and the like are notnecessary, so that a highly accurate focusing performance can beachieved. However, to detect the peak of a contrast value, the focuslens group 72 has to be driven until the focus lens group 72 passesthrough a position where the contrast value reaches its peak.Accordingly, the focus lens group 72 has to be moved beyond the positionwhere the contrast value reaches the peak first and then be moved backto the position corresponding to the peak of the contrast value, andthus, a backlash generated in a focus lens group driving system due tothe operation of driving the focus lens group 72 in back and forthdirections has to be removed.

(Hybrid AF)

Subsequently, the shooting operation of the camera system using hybridAF will be described with reference to FIG. 14.

Steps (Steps Sc1-Sc5) from the step in which the power switch 40 a isturned on to the step in which the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down arethe same as Steps Sa1-Sa5 in phase difference detection AF.

When the release button 40 b is pressed halfway down by the user (StepSc5), the body microcomputer 50 amplifies an output from the line sensor24 a of the phase difference detection unit 20, and then performs anoperation by the arithmetic circuit, thereby determining whether or notan object image has been brought into focus (Step Sc6). Furthermore, thebody microcomputer 50 obtains information regarding whether the objectis in front focus or back focus and the Df amount, and then, obtainsdefocus information (Step Sc7). Thereafter, the process proceeds to StepSc10.

In parallel with Steps Sc6 and Sc7, photometry is performed (Step Sc8),and also image blur detection is started (Step Sc9). Steps Sc6 and Sc7are the same as Steps Sa9 and Sa10 in phase difference detection AF.Thereafter, the process proceeds to Step Sc10. Note that, after StepSc9, the process may also proceed to Step Sa11, instead of Sc10.

As decried above, in this embodiment, using light which has entered theimaging device 10 and has been transmitted through the imaging device10, the above-described focus detection based on a phase difference isperformed. Thus, in parallel with the above-described focus detection,photometry can be performed using the imaging device 10.

In Step Sc10, the body microcomputer 50 drives the focus lens group 72based on the defocus information obtained in Step Sc7.

The body microcomputer 50 determines whether or not a contrast peak hasbeen detected (Step Sc11). If the contrast peak has no't been detected(NO), driving of the focus lens group 72 (Step Sc10) is repeated. If thecontrast peak has been detected (YES), driving of the focus lens group72 is halted, and the focus lens group 72 is moved to a position wherethe contrast value has reached the peak. Then, the process proceeds toStep Sa11.

Specifically, in Steps Sc10 and Sc11, it is preferable that, based onthe defocus direction and the defocus amount calculated in Step Sc7, thefocus lens group 72 is moved at high speed, and then, the focus lensgroup 72 is moved at lower speed than the high speed to detect thecontrast peak.

In this case, it is preferable that an moving amount of the focus lensgroup 72 which is moved based on the calculated defocus amount (i.e., aposition to which the focus lens group 72 is to be moved) is set to bedifferent from that in Step Sa7 in phase difference detection AF.Specifically, in Step Sa7 in phase difference detection AF, the focuslens group 72 is moved to a position which is estimated as a focusposition, based on the defocus amount. In contrast, in Step Sc10 inhybrid AF, the focus lens group 72 is driven to a position shiftedforward or backward from the position estimated as a focus positionbased on the defocus amount. Thereafter, in hybrid AF, the contrast peakis detected while the focus lens group 72 is driven toward the positionestimated as the focus position.

In Step Sa11, the body microcomputer 50 remains in a standby state untilthe release button 40 b is pressed all the way down by the user. A flowof steps after the release button 40 b is pressed all the way down isthe same as that of phase difference detection AF.

As has been described, in hybrid AF, first, defocus information isobtained by the phase difference detection unit 20, and the focus lensgroup 72 is driven based on the defocus information. Then, the positionof the focus lens group 72 at which the contrast value calculated basedon an output from the imaging device 10 reaches its peak is detected,and the focus lens group 72 is moved to the position. Thus, defocusinformation can be detected before driving the focus lens group 72, andtherefore, as opposed to contrast detection AF, the step of tentativelydriving the focus lens group 72 is not necessary. This allows reductionin processing time for autofocusing. Moreover, an object image isbrought into focus by contrast detection AF eventually, and therefore,particularly, an object having a repetitive pattern, an object havingextremely low contrast, and the like can be brought into focus withhigher accuracy than in phase difference detection AF.

Since defocus information is obtained by the phase difference detectionunit 20 using light transmitted through the imaging device 10,photometry by the imaging device 10 can be performed in parallel withobtaining defocus information by the phase difference detection unit 20,although hybrid AF includes phase difference detection. As a result, amirror for dividing a part of light from an object does not have to beprovided for phase difference detection, and also, a photometry sensordoes not have to be additionally provided. Furthermore, photometry canbe performed before the release button 40 b is pressed all the way down,so that a release time lag can be reduced. In the configuration in whichphotometry is performed before the release button 40 b is pressed allthe way down, photometry can be performed in parallel with obtainingdefocus information, thereby preventing increase in processing timeafter the release button 40 b is pressed halfway down.

—Variations—

In the above description, after the release button 40 b is pressed allthe way down, stopping down is performed immediately before exposure. Inthe following description, a variation configured so that, in phasedifference detection AF and hybrid AF, before the release button 40 b ispressed all the way down, stopping down is performed before autofocusingwill be described.

(Phase Difference Detection AF)

Specifically, first, the shooting operation of the camera system inphase difference detection AF according to the variation will bedescribed with reference to FIG. 15.

Steps (Steps Sd1-Sd5) from the step in which the power switch 40 a isturned on to the step in which the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down arethe same as Steps Sa1-Sa5 in phase difference detection AF which havebeen described above.

When the release button 40 b is pressed half way down by a user (StepSd5), image blur detection is started (Step Sd6), and in parallel withStep Sd6, photometry is performed (Step Sd7). Steps Sd5 and Sd6 are thesame as Steps Sa9 and Sa10 in phase difference detection AF.

Thereafter, an aperture value at the time of exposure is obtained basedon a result of photometry in Step Sd7, and whether or not the obtainedaperture value is larger than a predetermined aperture threshold valueis determined (Step Sd8). Then, when the obtained aperture value islarger than the predetermined aperture threshold value (YES), theprocess proceeds to Step Sd10. When the obtained value is equal to orsmaller than the predetermined aperture threshold value (NO), theprocess proceeds to Step Sd9. In Step Sd9, the body microcomputer 50drives the aperture section 73 via the lens microcomputer 80 to attainthe obtained aperture value.

In this case, the predetermined aperture threshold value is set to beabout an aperture value at which defocus information can be obtainedbased on an output of the line sensor 24 a of the phase differencedetection unit 20. That is, assuming that the aperture value obtainedbased on the result of photometry is larger than the aperture thresholdvalue, if the aperture section 73 is stopped down to the aperture value,defocus information cannot be obtained by the phase difference detectionunit 20. Therefore, the aperture section 73 is not stopped down, and theprocess proceeds to Step Sd10. On the other hand, when the aperturevalue obtained based on the result of photometry is equal to or smallerthan the aperture threshold value, the aperture section 73 is stoppeddown to the aperture value, and then, the process proceeds to Step Sd10.

In Steps Sd10-Sd12, similarly to Steps Sa6-Sa8 in phase differencedetection AF described above, the body microcomputer 50 obtains defocusinformation based on an output from the line sensor 24 a of the phasedifference detection unit 20 (Step Sd10), drives the focus lens group 72based on the defocus information (Step Sd11), and determines whether ornot an object image has been brought into focus (Step Sd12). After anobject image has been brought into focus, the process proceeds to StepSa11.

In Step Sa11, the body microcomputer remains in a standby state untilthe release button 40 b is pressed all the way down by the user. A flowof steps after the release button 40 b is pressed all the way down isthe same as that of phase difference detection AF described above.

It should be noted that only when it is determined in Step Sd8 that theaperture value obtained based on the result of photometry is larger thanthe predetermined aperture threshold value, stopping down of theaperture section 73 is performed in Step Sa14. That is, when it isdetermined in Step Sd8 that the aperture value obtained based on theresult of photometry is equal to or smaller than the predeterminedaperture threshold value, Step Sa14 does not have to be performedbecause stopping down of the aperture section 73 is performed beforehandin Step Sd9.

As described above, in the shooting operation of the camera system inphase difference detection AF according to the variation, when theaperture value at the time of exposure obtained based on the result ofphotometry is about a value at which phase difference detection AF canbe performed, the aperture section 73 is stopped down in advance ofexposure before autofocusing. Thus, stopping down of the aperturesection 73 does not have to be performed after the release button 40 bis pressed all the way down, so that a release time lag can be reduced.

(Hybrid AF)

Next, the shooting operation of the camera system in hybrid AF accordingto the variation will be described with reference to FIG. 16.

Steps (Steps Se1-Se5) from the step in which the power switch 40 a isturned on to the step in which the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down arethe same as Steps Sa1-Sa5 in phase difference detection AF which havebeen described above.

When the release button 40 b is pressed half way down by a user (StepSe5), image blur detection is started (Step Se6), and in parallel withStep Se6, photometry is performed (Step Se7). Steps Se6 and Se7 are thesame as Steps Sa9 and Sa10 in phase difference detection AF.

Thereafter, an aperture value at the time of exposure is obtained basedon a result of photometry in Step Se7, and whether or not the obtainedaperture value is larger than a predetermined aperture threshold valueis determined (Step Se8). Then, when the obtained aperture value islarger than the predetermined aperture threshold value (YES), theprocess proceeds to Step Se10. When the obtained value is equal to orsmaller than the predetermined aperture threshold value (NO), theprocess proceeds to Step Se9. In Step Se9, the body microcomputer 50drives the aperture section 73 via the lens microcomputer 80 to attainthe obtained aperture value.

In this case, the predetermined aperture threshold value is set to beabout an aperture value at which a peak of a contrast value calculatedfrom an output of the imaging device 10 can be detected. That is,assuming that the aperture value obtained based on the result ofphotometry is larger than the aperture threshold value, if the aperturesection 73 is stopped down to the aperture value, contrast peakdetection, which will be described later, cannot be performed.Therefore, the aperture section 73 is not stopped down, and the processproceeds to Step Se10. On the other hand, when the aperture valueobtained based on the result of photometry is equal to or smaller thanthe aperture threshold value, the aperture section 73 is stopped down tothe aperture value, and then, the process proceeds to Step Se10.

In Steps Se10-Se12, similarly to Steps Sc6, Sc7, Sc10 and Sc11 in normalhybrid AF described above, the body microcomputer 50 obtains defocusinformation based on an output from the line sensor 24 a of the phasedifference detection unit 20 (Steps Se10 and Se11), drives the focuslens group 72 based on the defocus information (Step Se12), and detectsthe contrast peak to move the focus lens group 72 to a position wherethe contrast value has reached the peak (Step Se13).

Thereafter, in Step Sa11, the body microcomputer remains in a standbystate until the release button 40 b is pressed all the way down by theuser. A flow of steps after the release button 40 b is pressed all theway down is the same as that of normal phase difference detection AFdescribed above.

It should be noted that only when it is determined in Step Se8 that theaperture value obtained based on the result of photometry is larger thanthe predetermined aperture threshold value, stopping down of theaperture section 73 is performed in Step Sa14. That is, when it isdetermined in Step Se8 that the aperture value obtained based on theresult of photometry is equal to or smaller than the predeterminedaperture threshold value, Step Sa14 does not have to be performedbecause stopping down of the aperture section 73 is performed beforehandin Step Se9.

As described above, in the shooting operation of the camera system inhybrid AF according to the variation, when the aperture value at thetime of exposure obtained based on the result of photometry is about avalue at which contrast detection AF can be performed, the aperturesection 73 is stopped down in advance of exposure before autofocusing.Thus, stopping down of the aperture section 73 does not have to beperformed after the release button 40 b is pressed all the way down, andtherefore, a release time lag can be reduced.

—Continuous Shooting Mode—

In the above description, each time the release button 40 b is pressedall the way down, a single image is shot. The camera 100 has acontinuous shooting mode in which a plurality of images are shot bypressing the release button 40 b all the way down once.

The continuous shooting mode will be described hereinafter withreference to FIGS. 17 and 18. In the following description, it isassumed that hybrid AF according to the variation is performed. Notethat the continuous shooting mode is not limited to hybrid AF accordingto the variation, but can be employed in any configuration using phasedifference detection AF, contrast detection AF, hybrid AF, phasedifference detection AF according to the variation, or the like.

Steps (Steps Sf1-Sf13) from the step in which the power switch 40 a isturned on to the step in which a release button 40 b is pressed halfwaydown and the focus lens group 72 is moved to the position where thecontrast value has reached the peak are the same as Steps Se1-Se13 inhybrid AF according to the variation.

After the focus lens group 72 is moved to the position where thecontrast value has reached the peak, the body microcomputer 50 causesthe memory section to store a distance between two object images formedon the line sensor 24 a at that time (i.e., when an object image hasbeen brought into focus using contrast detection AF) (Step Sf14).

Thereafter, in Step Sf15, the body microcomputer remains in a standbystate until the release button 40 b is pressed all the way down by theuser. When the release button 40 b is pressed all the way down by theuser, exposure is performed in the same manner as in Steps Sa12-Sa17 inphase difference detection AF.

Specifically, the body microcomputer 50 temporarily puts the shutterunit 42 into a close state (Step Sf16), image blur correction is started(Step Sf17), and if the aperture section 73 is not stopped down in StepSf9, the aperture section 73 is stopped down based on a result ofphotometry (Step Sf18). Thereafter, the shutter unit 42 is put into anopen state (Step Sf19), exposure is started (Step Sf20), and the shutterunit 42 is put into a close state (Step Sf21) to terminate the exposure.

After the exposure is terminated, whether or not the release button 40 bhas been released from being pressed all the way down is determined(Step Sf22). When the release button 40 b has been released (YES), theprocess proceeds to Steps Sf29 and Sf30. On the other hand, when therelease button 40 b is continuously pressed all the way down (NO), theprocess proceeds to Step Sf23 to perform continuous shooting.

When the release button 40 b is continuously pressed all the way down,the body microcomputer 50 puts the shutter unit 42 into an open state(Step Sf23), and phase difference detection AF is performed (StepsSf24-Sf26).

Specifically, an in-focus state of an object image in the imaging device10 is detected via the phase difference detection unit 20 (Step Sf24),defocus information is obtained (Step Sf25), and the focus lens group 72is driven based on the defocus information (Step Sf26).

In this case, in hybrid AF before the release button 40 b is pressed allthe way down, a distance between two object images formed on the linesensor 24 a is compared to a reference distance which has been setbeforehand to obtain the defocus information (Step Sf11). In contrast,in Steps Sf24 and Sf25 after the release button 40 b is pressed all theway down, the distance between two object images formed on the linesensor 24 a is compared to the distance of two object images formed onthe line sensor 24 a which has been stored in Step Sf14 after contrastdetection AF in hybrid AF to obtain an in-focus state and defocusinformation.

After phase difference detection AF is performed in the above-describedmanner, the body microcomputer 50 determines whether or not it is atiming of outputting a signal (i.e., an exposure start signal) forstarting exposure from the body microcomputer 50 to the shutter controlsection 51 and the imaging unit control section 52 (Step Sf27). Thisoutput timing of the exposure start signal is a timing of performingcontinuous shooting in continuous shooing mode. When it is not theoutput timing of the exposure start signal (NO), phase distancedetection AF is repeated (Steps Sf24-Sf26). On the other hand, when itis the output timing of the exposure start signal (YES), driving of thefocus lens group 72 is halted (Step Sf28) to perform exposure (StepSf20).

Note that after the focus lens group 72 is halted, it is necessary tosweep out, before starting exposure, electrical charges accumulated inthe light receiving sections 11 b of the imaging device 10 during phasedifference detection AF. Therefore, electrical charges in the lightreceiving sections 11 b are swept out using an electronic shutter, orthe shutter unit 42 is temporarily put into a close state to sweep outelectrical charges in the light receiving sections 11 b, and then theshutter unit 42 is put into an open state to start exposure.

After the exposure is terminated, whether or not the release button 40 bhas been released from being pressed all the way down is determinedagain (Step Sf22). As long as the release button 40 b is pressed all theway down, phase difference detection AF and exposure are repeated (StepsSf23-Sf28 and Steps Sf20 and Sf21).

When the release button 40 b has been released from being pressed allthe way down, image blur correction is terminated (Step Sf29), and also,the aperture section 73 is opened up (Step Sf30) to put the shutter unit42 into an open state (Step Sf31).

After completing resetting, when a shooting sequence is terminated, theprocess returns to Step Say, and the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down.

When the power switch 40 a is turned off (Step Sf32), the bodymicrocomputer 50 moves the focus lens group 72 to a predeterminedreference position which has been set beforehand (Step Sf33), and putsthe shutter unit 42 into a close state (Step Sf34). Then, respectiveoperations of the body microcomputer 50 and other units in the camerabody 4, and the lens microcomputer 80 and other units in theinterchangeable lens 7 are halted.

As described above, in the shooting operation of the camera system inthe continuous shooting mode, phase difference detection AF can beperformed between exposures during continuous shooting, so that a highfocus performance can be realized.

Also, since autofocusing is performed using phase difference detectionAF in this case, the defocus direction can be instantly obtained, andthus, an object can be instantly brought into focus even in a short timebetween shootings continuously performed.

Furthermore, as opposed to a known technique, even in phase differencedetection AF, a movable mirror for phase difference detection does nothave to be provided. Thus, a release time lag can be reduced, and also,power consumption can be reduced. Moreover, according to the knowntechnique, a release time lag corresponding to the vertical movement ofthe movable mirror is generated, and thus, when an object is a movingobject, it is necessary to predict the movement of the moving objectduring the release time lag and then shoot an image. However, accordingto this embodiment, there is no release time lag corresponding to thevertical movement of the movable mirror, and therefore, focus can beachieved while following the movement of an object until immediatelybefore exposure.

In phase difference detection AF during continuous shooting, as thereference distance between two object images formed on the line sensor24 a based on which whether or not an object image has been brought intofocus is determined, the distance between two object images formed onthe line sensor 24 a when the release button 40 b is pressed halfwaydown and an object image has been brought into focus by contrastdetection AF is used. Thus, highly accurate autofocusing whichcorresponds to actual equipment and actual shooting conditions can beperformed.

At the time of shooting for the first frame in the continuous shootingmode, the autofocusing method is not limited to hybrid AF. Phasedifference detection AF or contrast detection AF may be used. However,as described above, if AF such as hybrid AF and contrast detection AF inwhich focus adjustment is eventually performed based on the contrastvalue is employed at the time of shooting for the first frame, phasedifference detection AF at the time of shooting for second andsubsequent frames can be performed based on a highly accurate in-focusstate obtained at the time of shooting for the first frame. Note thatwhen phase difference detection AF is used, Step Sf14 is not performed,the distance between two object images formed on the line sensor 24 a iscompared to the reference distance which has been set beforehand toobtain an in-focus state and defocus information.

Not only in the continuous shooting mode but also in normal shooting,the camera system may be configured so that when an object is a movingobject, phase difference detection AF is performed until the releasebutton 40 b is pressed all the way down even after an object image hasbeen brought into focus.

—Low Contrast Mode—

The camera 100 of this embodiment is configured so that the autofocusingmethod is switched according to the contrast of an object. That is, thecamera 100 has a low contrast mode in which shooting is performed undera low contrast condition.

The low contrast mode will be described hereinafter with reference toFIG. 19. In the following description, it is assumed that hybrid AF isperformed. Note that the low contrast mode is not limited to hybrid AF,but can be employed in any configuration using phase differencedetection AF, contrast detection AF, phase difference detection AFaccording to the variation, hybrid AF according to the variation, or thelike. Steps (Steps Sg1-Sg5) from the step in which the power switch 40 ais turned on to the step in which the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down arethe same as Steps Sa1-Sa5 in phase difference detection AF.

When the release button 40 b is pressed halfway down by a user (StepSg5), the body microcomputer 50 amplifies an output from the line sensor24 a of the phase difference detection unit 20, and then performs anoperation by the arithmetic circuit (Step Sg6). Then, whether or not alow contrast state has occurred is determined (Step Sg7). Specifically,it is determined whether or not a contrast value is high enough todetect respective positions of two object images formed on the linesensor 24 a based on the output from the line sensor 24 a.

When the contrast value is high enough to detect the positions of thetwo object images (NO), it is determined that a low contrast state hasnot occurred, and the process proceeds to Step Sg8 to perform hybrid AF.Note that Steps Sg8-Sg10 are the same as Steps Sc7, Sc10 and Sc11 inhybrid AF.

On the other hand, when the contrast value is not high enough to detectthe position of the two object images (YES), it is determined that a lowcontrast state has occurred, and the process proceeds to Step Sg11 toperform contrast detection AF. Note that Steps Sg11-Sg15 are the same asSteps Sb6-Sb10 in contrast detection AF.

After hybrid AF or contrast detection AF is preformed in theabove-described manner, the process proceeds to Step Sa11.

In parallel with this autofocus operation (Steps Sg6-Sg15), photometryis performed (Step Sg16), and image blur detection is started (StepSg17). Steps Sg16 and Sg17 are the same as Steps Sa9 and Sa11) in phasedifference detection AF. Thereafter, the process proceeds to Step Sa11.

In Step Sa11, the body microcomputer remains in a standby state untilthe release button 40 b is pressed all the way down by the user. A flowof steps after the release button 40 b is pressed all the way down isthe same as that of normal hybrid detection AF.

That is, in the low contrast mode, when the contrast at the time ofshooting is high enough to perform phase difference detection AF, hybridAF is performed. On the other hand, when the contrast at the time ofshooting is so low that phase difference detection AF cannot beperformed, contrast detection AF is performed.

In this embodiment, first, it is determined whether or not an in-focusstate can be detected using phase difference detection based on theoutput of the line sensor 24 a of the phase difference detection unit20, and then, hybrid AF or contrast detection AF is selected. However,the present invention is not limited thereto. For example, the camerasystem may be configured so that after the release button 40 b ispressed halfway down, the contrast value is obtained from an output ofthe imaging device 10 to determine whether or not the contrast valueobtained from the output of the imaging device 10 is higher than apredetermined value before a phase difference focus is detected (i.e.,between Steps Sg5 and Sg6 in FIG. 19). The predetermined value is set tobe about a contrast value at which a position of an object image formedon the line sensor 24 a can be detected. That is, the camera system maybe configured so that, when the contrast value obtained from the outputof the imaging device 10 is approximately equal to or larger than avalue at which an in-focus state can be detected using phase differencedetection, hybrid AF is performed and, on the other hand, when thecontrast value obtained from the output of the imaging device 10 issmaller than the value at which an in-focus state can be detected usingphase difference detection, contrast detection AF is performed.

Also, in this embodiment, when an in-focus state can be detected usingphase difference detection, hybrid AF is performed. However, the camerasystem may be configured so that, when an in-focus state can be detectedusing phase difference detection, phase difference detection AF isperformed.

As described above, in the camera 100 including the imaging unit 1 forreceiving light transmitting through the imaging device 10 by the phasedifference detection unit 20, the movable mirror of the known techniquefor guiding light to the phase difference detection unit is notprovided, but phase difference detection AF (including hybrid AF) andcontrast detection AF can be performed. Thus, a highly accurate focusperformance can be realized by selecting one of phase differencedetection AF and contrast detection AF according to the contrast.

—AF Switching According to Interchangeable Lens—

Furthermore, the camera 100 of this embodiment is configured so that theautofocusing method is switched according to the type of theinterchangeable lens 7 attached to the camera body 4.

An AF switching function according to the type of the interchangeablelens will be described hereinafter with reference to FIG. 20. In thefollowing description, it is assumed that hybrid AF is performed. Notethat the AF switching function according to the interchangeable lens isnot limited to hybrid AF, but can be employed in any configuration usingphase difference detection AF, contrast detection AF, phase differencedetection AF according to the variation, hybrid AF according to thevariation, or the like.

Steps (Steps Sh1-Sh5) from the step in which the power switch 40 a isturned on to the step in which the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down arethe same as Steps Sa1-Sa5 in phase difference detection AF.

When the release button 40 b is pressed half way down by a user (StepSh5), photometry is performed (Step Sh6), and in parallel with Step Sh6,image blur detection is started (Step Sh7). Steps Sh6 and Sh7 are thesame as Steps Sa9 and Sa10 in phase difference detection AF. Note thatthe photometry and image blur detection may be performed in parallelwith an autofocus operation, which will be described later.

Thereafter, the body microcomputer 50 determines whether or not theinterchangeable lens 7 is a reflecting telephoto lens produced by athird party or a smooth trans focus (STF) lens based on information fromthe lens microcomputer 80 (Step Sh8). When the interchangeable lens 7 isa reflecting telephoto lens produced by a third party or a STF lens(YES), the process proceeds to Step Sh13 to perform contrast detectionAF. Note that Steps Sh13-Sh17 are the same as Steps Sb6-Sb10 in contrastdetection AF.

On the other hand, when the interchangeable lens 7 is not either areflecting telephoto lens produced by a third party or a STF lens (NO),the process proceeds to Step Sh9 to perform hybrid AF. Note that StepsSh9-Sh12 are the same as Steps Sc6, Sc7, Sc10 and Sc11 in hybrid AF.

After contrast detection AF or hybrid AF is performed in theabove-described manner, the process proceeds to Step Sa11.

In Step Sa11, the body microcomputer remains in a standby state untilthe release button 40 b is pressed all the way down by the user. A flowof steps after the release button 40 b is pressed all the way down isthe same as that of hybrid AF.

That is, when the interchangeable lens 7 is a reflecting telephoto lensproduced by a third party or a STF lens, phase difference detectionmight not be performed with high accuracy, and therefore, hybrid AF(specifically, phase difference detection AF) is not performed, butcontrast detection AF is performed. On the other hand, when theinterchangeable lens 7 is not either a reflecting telephoto lensproduced by a third party or a STF lens, hybrid AF is performed. Thatis, the body microcomputer 50 determines whether or not it is ensuredthat an optical axis of the interchangeable lens 7 properly extends sothat phase difference detection AF can be performed. Then, only when itis ensured that the optical axis of the interchangeable lens 7 properlyextends so that phase difference detection AF can be performed, hybridAF is performed. If it is not ensured that the optical axis of theinterchangeable lens 7 properly extends so that phase differencedetection AF can be performed, contrast detection AF is performed.

As described above, in the camera 100 including the imaging unit 1 forreceiving light transmitting through the imaging device 10 by the phasedifference detection unit 20, the movable mirror of the known techniquefor guiding light to the phase difference detection unit is notprovided, but phase difference detection AF (including hybrid AF) andcontrast detection AF can be performed. Thus, a highly accurate focusperformance can be realized by selecting one of phase differencedetection AF and contrast detection AF according to the type of theinterchangeable lens 7.

According to this embodiment, it is determined which of hybrid AF andcontrast detection AF is to be performed depending on whether or not theinterchangeable lens 7 is a reflecting telephoto lens produced by athird party or a STF lens. However, the present invention is not limitedthereto. The camera system may be configured to determine which ofhybrid AF and contrast detection AF is to be performed depending on onlywhether or not the interchangeable lens 7 is produced by a third party,regardless of whether or not the interchangeable lens 7 is a reflectingtelephoto lens or a STF lens.

Also, according to this embodiment, the camera system is configured sothat when the interchangeable lens 7 is not either a reflectingtelephoto lens produced by a third party or a STF lens, hybrid AF isperformed. However, the camera system may be configured so that when theinterchangeable lens 7 is not either a reflecting telephoto lensproduced by a third party or a STF lens, phase difference detection AFis performed.

Therefore, according to this embodiment, the imaging device 10 isconfigured so that light passes through the imaging device 10, and thephase difference detection unit 20 for receiving light which has passedthrough the imaging device 10 to perform phase difference detection isprovided. Moreover, the body control section 5 controls the imagingdevice 10 and also controls driving of the focus lens group 72 at leastbased on a detection result of the phase difference detection unit 20 toperform focus adjustment. Thus, various types of processing using theimaging device 10 can be performed in parallel with autofocusing (phasedifference detection AF and hybrid AF which have been described above)using the phase difference detection unit 20, so that the processingtime can be reduced.

Also, in the above-described configuration, when light enters theimaging device 10, light also enters the phase difference detection unit20. Thus, even if various types of processing using the imaging device10 are not performed in parallel with autofocusing the phase differencedetection unit 20, switching between various types of processing usingthe imaging device 10 and autofocusing the phase difference detectionunit 20 can be performed in a simple manner by changing a control modeof the body control section 5. That is, compared to a knownconfiguration in which the direction in which light travels from anobject is switched between the direction toward an imaging device andthe direction toward a phase difference detection unit by moving amovable mirror forward/backward, the movable mirror does not have to bemoved forward/backward, so that switching between various types ofprocessing using the imaging device 10 and autofocusing the phasedifference detection unit 20 can be quickly performed. Also, noise isnot caused by moving the movable mirror forward/backward, and thus,switching between various types of processing using the imaging device10 and autofocusing the phase difference detection unit 20 can bequietly performed.

Thus, the convenience of the camera 100 can be improved.

Specifically, the imaging device 10 is configured so that light passesthrough the imaging device 10, and the phase difference detection unit20 for receiving light which has passed through the imaging device 10 toperform phase difference detection is provided, so that AF using thephase difference detection unit 20, such as the above-described phasedifference detection AF, and photometry using the imaging device 10 canbe performed in parallel. Thus, photometry does not have to be performedafter pressing the release button 40 b all the way down, thus resultingin reduction in a release time lag. Even in the configuration in whichphotometry is performed before the release button 40 b is pressed allthe way down, increase in processing time after the release button 40 bis pressed halfway down can be prevented by performing photometry inparallel with autofocusing. Furthermore, since photometry is performedusing the imaging device 10, there is no need to additionally provide aphotometry sensor. Also, a movable mirror for guiding light from anobject to the photometry sensor or the phase difference detection unitdoes not have to be provided. Therefore, power consumption can bereduced.

Also, the imaging device 10 is configured so that light passes throughthe imaging device 10, and the phase difference detection unit 20 forreceiving light which has passed through the imaging device 10 toperform phase difference detection is provided, so that the drivingdirection of the focus lens group 72 is determined based on a detectionresult of the phase difference detection unit 20, and then, contrastdetection AF based on an output of the imaging device 10 can be quicklyperformed as in the above-described hybrid AF. That is, switching fromphase difference detection by the phase difference detection unit 20 tocontrast detection using the imaging device 10 can be quickly performedby control of the body control section 5 without performing switchingthe optical path using a movable mirror, or the like, in a known manner,thereby reducing a time required for hybrid AF. A movable mirror is notneeded, and therefore, noise caused by such a movable mirror is notgenerated and hybrid AF can be performed quietly.

Furthermore, the body control section 5 performs photometry using theimaging device 10 and controls the aperture section 73 based on theresult of the photometry to adjust the amount of light, and then, phasedifference detection is performed by the phase difference detection unit20. Thus, stopping down does not have to be performed after the releasebutton 40 b is pressed all the way down, thus reducing a release timelag. Then, the imaging device 10 is configured so that light passesthrough the imaging device 10, and the phase difference detection unit20 for receiving light which has passed through the imaging device 10 toperform phase difference detection is provided, so that when photometryusing the imaging device 10 and phase difference detection using thephase difference detection unit 20 are performed in succession,switching between photometry by the imaging device 10 and phasedifference detection by the phase difference detection unit 20 can beperformed quickly and quietly by control of the body control section 5.

In the continuous shooting mode, the body control section 5 performs,based on the detection result of the phase difference detection unit 20,phase difference detection AF at the time of shooting for second andsubsequent frames. Thus, phase difference detection AF can be performedbetween frames during continuous shooting, so that the focusingperformance can be improved. Then, the imaging device 10 is configuredso that light passes through the imaging device 10, and the phasedifference detection unit 20 for receiving light which has passedthrough the imaging device 10 to perform phase difference detection isprovided, so that switching between exposure by the imaging device 10and AF by the phase difference detection unit 20 can be quickly andquietly performed. Thus, phase difference detection AF between framesduring continuous shooting can be realized.

Also, since autofocusing is performed using phase difference detectionAF in this case, the defocus direction can be instantly obtained, andthus, an object can be instantly brought into focus even in a short timebetween shootings continuously performed.

In shooting for the second and subsequent frames, phase differencedetection AF is continuously performed until a next shooting timing, andthus, even if an object moves between shootings continuously performed,it is possible to follow the movement of the object and to bring theobject in focus.

Furthermore, since there is no release time lag corresponding to themovement of a movable mirror in the forward/backward directions, it ispossible to follow the movement of the object to bring an object infocus until immediately before exposure. Thus, even if an object is amoving object, the object can be brought into focus with high accuracywithout performing moving object prediction.

At the time of shooting for a first frame in the continuous shootingmode, AF (i.e., contrast detection AF or hybrid AF) for eventuallyadjusting a focus based on a contrast value is performed. After anobject image has been brought into focus, phase difference detection isperformed by the phase difference detection unit 20, and a result of thedetection is stored. At the time of shooting for second and subsequentframes, phase difference detection AF is performed based on thedetection result of the phase difference detection unit 20 after thefocusing for the first frame. Thus, highly accurate autofocusing whichcorresponds to actual equipment and actual shooting conditions can beperformed.

In the low contrast mode, the body control section 5 performs focusadjustment at least based on the detection result of the phasedifference detection unit 20 when the contrast value of an object is apredetermined value or larger, and performs focus adjustment not usingthe detection result of the phase difference detection unit 20 but basedon an output of the imaging device 10 when the contrast value of theobject is smaller than the predetermined value. Thus, the object can bebrought into focus with high accuracy using AF using a suitableautofocusing method according to the contrast of the object.Specifically, the body control section 5 performs AF (i.e., phasedifference detection AF or hybrid AF) using the phase differencedetection unit 20 when the contrast value of the object is large enoughto perform phase difference detection AF, and performs contrastdetection AF when the contrast value of the object is so low that phasedifference detection AF cannot be performed. Thus, the object can bebrought into focus by AF using a suitable method which corresponds tothe contrast of the object, so that the object can be brought into focuswith high accuracy.

The body control section 5 switches an AF method between AF at leastbased on a detection result of the phase difference detection unit 20and AF based on an output of the imaging device 10 without using thedetection result of the phase difference detection unit 20 according tothe type of the interchangeable lens 7. Thus, focus can be achieved byAF using a suitable method which corresponds to the interchangeable lens7. Specifically, the body control section 5 performs contrast detectionAF when the interchangeable lens 7 is a reflecting telephoto lensproduced by a third party (i.e., produced by a different manufacturerfrom a manufacturer of the camera body 4), or a STF lens, and performsAF (i.e., phase difference detection AF of hybrid AF) at least using thephase difference detection unit 20 when the interchangeable lens 7 isnot a product by a third party or a reflecting telephoto lens, and alsonot a STF lens. In other words, only when the interchangeable lens 7ensured that an optical axis is so proper that phase differencedetection AF can be performed is attached to the camera body 4, hybridAF is performed. If it is not ensured that the optical axis of theinterchangeable lens 7 is so proper that phase difference detection AFcan be performed, contrast detection AF is performed. Thus, the objectimage can be brought into focus by AF using a suitable method whichcorresponds to the interchangeable lens 7, so that focus can be achievedwith high accuracy.

In the known configuration in which light directed from an object to theimaging device 10 is guided to a phase difference detection unitprovided at some other position than the back surface side of theimaging device 10 using a movable mirror or the like, accuracy in focusadjustment is not high because of a difference between the optical pathat the time of exposure and the optical path at the time of phasedifference detection, an arrangement error, and the like. In contrast,in this embodiment, the phase difference detection unit 20 receiveslight passing through the imaging device 10 to perform phase differencedetection, and thus, phase difference detection can be performed usingthe same optical path as that at the time of exposure. Also, a membersuch as a movable mirror which causes an error is not provided. Thus,the accuracy of focus adjustment based on phase difference detection canbe improved.

—During-Exposure AF Shooting Mode—

In the above-described normal shooting mode, driving of the focus lensgroup 72 is halted during exposure. However, the camera 100 has aduring-exposure AF shooting mode in which autofocusing is also performedduring exposure.

Specifically, the camera 100 is configured so that switching between theduring-exposure AF shooting mode in which exposure is performed whileperforming AF and the normal shooting mode in which the focus lens group72 is halted at the time of exposure can be performed by turning on/offthe during-exposure AF setting switch 40 e by a user.

The shooting mode is switched to the during-exposure AF shooting mode byturning on the during-exposure AF setting switch 40 e, but is alsoautomatically switched to the during-exposure AF shooting mode accordingto an object point distance (i.e., a distance from a lens to an object).That is, the camera body 4 is configured to be capable of calculatingthe object point distance and to perform, when the object point distanceis smaller than a predetermined distance, during-exposure AF shootingeven with the during-exposure AF setting switch being turned off.Specifically, the body microcomputer 50 calculates the object pointdistance based on a detection result from the absolute positiondetection section 81 a and lens information of the interchangeable lens7 and sets, when the calculated object point distance is a predeterminedthreshold or smaller, the shooting mode to be the during-exposure AFshooting mode. On the other hand, when the calculated object pointdistance is larger than the predetermined threshold, the bodymicrocomputer 50 sets the shooting mode to be the normal shooting mode.That is, the body control section 5 and the absolute position detectionsection 81 a serve as a distance detection section. Note that althoughthe body control section 5 has both of the functions as the distancedetection section for detecting a distance to an object and the controlsection for controlling the imaging device 10, a separate distancedetection section for detecting a distance to the object may beadditionally provided.

As described above, the camera 100 is configured so that the shootingmode is switched between the during-exposure AF shooting mode and thenormal shooting mode according to an operation by the user and also theshooting mode is automatically switched between the during-exposure AFshooting mode and the normal shooting mode according to the object pointdistance. Note that a method for detecting the object point distance isnot limited to the above-described method, but any means and method canbe employed.

Furthermore, in a macro shooting mode in which shooting (so-calledclose-up shooting) is performed with a setting suitable for shooting ofan object close to a camera, the shooting mode is automatically switchedto the during-exposure AF shooting mode. That is, the camera 100 has themacro shooting mode which is suitable for close-up shooting, and isconfigured so that the shooting mode can be switched between the macroshooting mode and the normal shooting mode by turning on/off the macrosetting switch 40 f by the user.

Specifically, the camera 100 is in the normal shooting mode when themacro setting switch 40 f is in an off state, and sets a moving range ofthe focus lens group 72 at the time of autofocusing to be a range whichallows focusing on an object at an object point distance of several cmto infinity. On the other hand, when the macro setting switch 40 f is inan on state, the camera 100 is in the macro shooting mode, and sets themoving range of the focus lens group 72 to be a range which allowsfocusing on an object at an object point distance of several cm toseveral tens cm. Shooting of an object at this object point distance isassumed as close-up shooting. That is, in the macro shooting mode, therange in which the focus lens group 72 is moved at the time ofautofocusing is set to be a limited range which is assumed to be a rangeof close-up shooting, and thus, the moving distance of the focus lensgroup 72 can be reduced and fast-focusing can be realized. When themacro setting switch 40 f is in an on state, the shooting mode isautomatically set to be the during-exposure AF shooting mode. That is,when an ON signal is input from the macro setting switch 40 f, the bodymicrocomputer 50 sets the moving range of the focus lens group 72 at thetime of autofocusing to be the above-described limited range, and theshooting mode to be the during-exposure AF shooting mode.

The shooting operation of the camera system in the during-exposure AFshooting mode will be described hereinafter with reference to FIGS. 21and 22.

In the following description, it is assumed that hybrid AF is performed.Note that the during-exposure AF shooting mode is not limited to hybridAF, but may be employed in any configuration using phase differencedetection AF, contrast detection AF, phase difference detection AFaccording to the variation, hybrid AF according to the variation, or thelike.

Steps (Steps Sk1-Sk11) from the step in which the power switch 40 a isturned on to the step in which the release button 40 b is pressedhalfway down and then autofocusing is completed, i.e., the focus lensgroup 72 is moved to the position where the contrast value has reachedthe peak are the same as Steps Sc1-Sc11 in hybrid AF in the normalshooting mode.

Thereafter, in Step Sk12, the body microcomputer 50 determines whetheror not the during-exposure AF setting switch 40 e is in an on state.When an ON signal from the during-exposure AF setting switch 40 e isinput (YES), the process proceeds to Step Sk16 to set a during-exposureAF flag to 1. When an ON signal from the during-exposure AF settingswitch 40 e is not input (NO), the process proceeds to Step Sk13.

In Step Sk13, the body microcomputer 50 determines whether or not theshooting mode is set to be the macro shooting mode, i.e., whether or notthe macro setting switch 40 f is in an on state. When an ON signal fromthe macro setting switch 40 f is input (YES), the step proceeds to StepSk16 to set the during-exposure AF flag to 1. When an ON signal from theduring-exposure AF setting switch 40 e is not input (NO), the processproceeds to Step Sk14.

In Step Sk14, the body microcomputer 50 calculates an object pointdistance from the focus lens group 72 to an object based on a detectionresult from the absolute position detection section 81 a and lensinformation of the interchangeable lens 7 to determine whether or notthe calculated object point distance is a predetermined threshold orsmaller. When the object point distance is the threshold or smaller(YES), the process proceeds to Step Sk16 to set the during-exposure AFflag to 1. When the object point distance is larger than the threshold,the process proceeds to Step Sk15 to set the during-exposure AF flag to0. The threshold is set to be an object point distance with whichclose-up shooting is assumed to be performed.

Note that after setting the during-exposure AF flag in Steps Sk15 andSk16, the process proceeds to Step Sk17.

In Step Sk17, the body microcomputer 50 remains in a standby state untilthe release button 40 b is pressed all the way down by the user. Whenthe release button 40 b is pressed all the way down by the user, whetheror not the during-exposure AF flag is 1 is determined in Step Sk18. Whenthe during-exposure AF flag is 0 (NO), the process proceeds to Step Sk19to perform exposure in the same manner as exposure in theabove-described hybrid AF, i.e., as in Sa12-Sa17 in phase differencedetection AF.

When the during-exposure AF flag is 1 (YES), the process proceeds toStep Sk19 to perform exposure, and also to Step Sk25 to perform phasedifference detection AF in parallel with Step Sk19.

Specifically, an output from the line sensor 24 a of the phasedifference detection unit 20 is amplified, and then, an operation by thearithmetic circuit obtains information regarding whether or not anobject image has been brought into focus, whether the object is in frontfocus or back focus, and the Df amount (Step Sk25). Thereafter, thefocus lens group 72 is driven in the defocus direction by the obtainedDf amount via the lens microcomputer 80 (Step Sk26). Then, whether ornot the shutter unit 42 is put in a close state is determined (StepSk27). If the shutter unit 42 is not in a close state (NO), the processreturns to Step Sk25 to repeat phase difference detection AF. If theshutter unit 42 is in a close state (YES), the process proceeds to StepSk28 to terminate phase difference detection AF. After terminating phasedifference detection AF, the process proceeds to Step Sk31. Note that inphase difference detection AF, light from an object has to enter theimaging unit 1, and therefore, phase difference detection AF istemporarily halted during Steps Sk19-Sk22 in which the shutter unit 42is in a close state.

Process in Steps Sk29-Sk34 after exposure has been terminated is thesame as process after exposure in the above-described hybrid AF, i.e.,in Steps Sa18-Sa23 in phase difference detection AF.

That is, in the during-exposure AF shooting mode, phase differencedetection AF is executed during exposure of the imaging device 10. Thephase difference detection AF continuously performed while exposure isperformed. Herein, “during exposure” can be also referred to as “duringa period of still image shooting by the imaging device 10”, “during aperiod of video signal storing by the imaging device 10”, “during aperiod of electrical charge storing by the imaging device 10”, or thelike.

The during-exposure AF shooting mode is intentionally set by the user byoperating the during-exposure AF setting switch 40 e, and also, isautomatically set when the shooting mode is the macro shooting mode orwhen the object point distance is very short. In many cases, so-calledclose-up shooting in which the shooting mode is the macro shooting modeor in which the object point distance is very short is performedindoors, compared to normal shooting other than close-up shooting. Thatis, close-up shooting is performed in a dark environment in many cases,and thus, the shutter speed has to be reduced to set an exposure time tobe long. In such a condition, the influence of the movement (hereinafteralso referred to as “camera shake”) of the camera body 4 due to handshake of the user and the like, and the movement of an object itself(hereinafter also referred to as “object shake”) on shooting isincreased.

In general, it has been known that an image blur correction mechanism isprovided to reduce the influence of camera shake on shooting. The imageblur correction mechanism is a mechanism for correcting an image blur inan plane perpendicular to an optical axis, and does not correct an imageblur in the direction along the optical axis. In this embodiment, thecamera 100 includes the blur correction unit 45 for moving the imagingunit 1 in an plane perpendicular to the optical axis X, and the blurcorrection lens driving section 74 a for moving the blur correction lens74 in a plane perpendicular to the optical axis X. The blur correctionunit 45 and the blur correction lens driving section 74 a correct animage blur in a plane perpendicular to the optical axis X, but cannotcorrect an image blur in the direction along the optical axis X.

Therefore, in the during-exposure AF shooting mode of this embodiment,autofocusing is performed during exposure. Thus, an imaging blur in thedirection along the optical axis X during exposure is reduced. Sinceautofocusing during the exposure is performed using phase differencedetection AF, the defocus direction can be instantly obtained, and thus,an object image can be instantly brought into focus even in a short timeduring which exposure is performed.

Then, as described above, the imaging device 10 is configured so thatlight passes through the imaging device 10, and the phase differencedetection unit 20 is configured to receive light which has passedthrough the imaging device 10 to detect a phase difference, and thus,phase difference detection AF while performing exposure of the imagingdevice 10 can be realized. Note that in the case of AF such as contrastdetection AF and the like using a signal from the imaging device 10, AFcannot be performed during exposure of the imaging device 10, in otherwords, during a period of image signal storing by the imaging device 10(i.e., the electrical charge storing period in this embodiment).

When each of the during-exposure AF setting switch 40 e and the macrosetting switch 40 f is in an off state, whether or not to performclose-up shooting is determined based on the object point distance.Then, if it is determined to perform close-up shooting, the shootingmode is set to be the during-exposure AF shooting mode. Thus, even whenthe user does not realize that shooting is being performed in acondition where the influence of hand shake on the direction along theoptical axis X is large, the camera 100 automatically determines thatshooting is being performed in such a shooting condition to correct animage blur in the direction along the optical axis X. If close-upshooting is not to be performed, i.e., the object point distance islong, the influence of hand shake in the direction along the opticalaxis X on shooting is small, so that autofocusing during exposure is notperformed, thus resulting in reduction in power consumption.

Note that although autofocusing performed before exposure, i.e., beforethe release button 40 b is pressed all the way down may be any one ofphase difference detection AF, contrast detection AF and hybrid AF,autofocusing during exposure is phase difference detection AF.

Also, in this embodiment, the during-exposure AF flag determination isperformed immediately after the release button 40 b is pressed all theway down, but the present invention is not limited thereto. For example,the camera 100 may be configured so that the during-exposure AF flagdetermination is performed at the time of starting exposure and, if theshooting mode is the during-exposure AF shooting mode, phase differencedetection AF is started simultaneously with the start of exposure.

Therefore, according to this embodiment, the imaging device 10 isconfigured so that light passes through the imaging device 10, and thephase difference detection unit 20 is configured to receive light whichhas passed through the imaging device 10 to perform phase differencedetection, thus realizing phase difference detection AF while performingexposure of the imaging device 10. In this case, autofocusing is phasedifference detection AF, and thus, the defocus direction and the defocusamount can be instantly obtained, and an object can be quickly broughtinto focus. As a result, autofocusing can be performed even in a shottime during which exposure is performed.

Also, phase difference detection AF during exposure is continuouslyperformed entirely during the exposure, and thus, highly accurateautofocusing can be performed.

Furthermore, by using exposure while performing phase differencedetection AF in the macro shooting mode or in close-up shooting usedwhen the object point distance is small, an image blur in the directionalong the optical axis generated due to camera shake or object shake canbe reduced.

Also, with the during-exposure AF setting switch 40 e provided, the usercan set the during-exposure AF shooting mode at the user's option.Therefore, the user can flexibly use the during-exposure AF shootingmode not only in close-up shooting but also when the user wants toreduce image blur in the direction along the optical axis.

Second Embodiment

Next, a camera as an imaging apparatus according to a second embodimentwill be described.

As shown in FIG. 23, a camera 200 according to the second embodimentincludes a finder optical system 6.

—Configuration of Camera Body—

A camera body 204 further includes, in addition to components of thecamera body 4 of the first embodiment, a finder optical system 6 forviewing an object image through a finder 65, and a semi-transparentquick return mirror 46 for guiding incident light from theinterchangeable lens 7 to the finder optical system 6.

The camera body 204 has a finder shooting mode in which shooting isperformed while a user views an object image through the finder opticalsystem 6, and a live view shooting mode in which shooting is performedwhile a user views an object image through the image display section 44.The camera body 204 is provided with a finder mode setting switch 40 g.The shooting mode is set to be the finder shooting mode is set byturning on the finder mode setting switch 40 g, and to be the live viewshooting mode by turning off the finder mode setting switch 40 g.

The finder optical system 6 includes a finder screen 61 on whichreflected light from the quick return mirror 46 forms an image, apentaprism 62 for converting an object image projected on the finderscreen 61 into an erected image, an eye lens 63 for enlarging theprojected object image for viewing, an in-finder display section 64 fordisplaying various kinds of information in a finder viewing field, and afinder 65 provided on a back surface side of the camera body 204.

That is, the user can observe an object image formed on the finderscreen 61 through the finder 65 via the pentaprism 62 and the eye lens63.

A body control section 205 further includes, in addition to componentsof the body control section 5 of the first embodiment, a mirror controlsection 260 for controlling flip-up of the quick return mirror 46, whichwill be described later, based on a control signal from the bodymicrocomputer 50.

The quick return mirror 46 is a semi-transparent mirror capable ofreflecting and transmitting incident light, and is configured to becapable of pivotally moving in front of the shutter unit 42 between areflection position (see a solid line of FIG. 23) which is on an opticalpath X extending from an object to the imaging unit 1 and a retractedposition (see a chain double-dashed line of FIG. 23) which is off theoptical path X and is located adjacent to the finder optical system 6.At the reflection position, the quick return mirror 46 divides incidentlight into reflected light toward the finder optical system 6 andtransmitted light to the back surface side of the quick return mirror46. The quick return mirror 46 serves as a movable mirror. Thereflection position corresponds to a first position, and the retractedposition corresponds to a second position.

Specifically, the quick return mirror 46 is arranged in front of theshutter unit 42 (i.e., at an object side), and pivotally supported aboutan axis Y which is located above and in front of the shutter unit 42 andhorizontally extends. The quick return mirror 46 is biased toward aretracted position by a bias spring (not shown). The quick return mirror46 is moved to the reflection position by the bias spring being wound upby a motor (not shown) for opening and closing the shutter unit 42. Thequick return mirror 46 which has been moved to the reflection positionis engaged with an electromagnet or the like at the refection position.Then, this engagement is released, thereby causing the quick returnmirror 46 to be pivotally moved to the retracted position by force ofthe bias spring.

That is, to guide a part of incident light to the finder screen 61, thebias spring is wound up by the motor, thereby causing the quick returnmirror 46 to be positioned at the reflection position. To guide theentire incident light to the imaging unit 1, the engagement with theelectromagnet or the like is released, thereby causing the quick returnmirror 46 to be pivotally moved to the retracted position by elasticforce of the bias spring.

As shown in FIGS. 24(A)-24(C), a light shielding plate 47 is connectedto the quick return mirror 46. The light shielding plate 47 isconfigured to interact with the quick return mirror 46, and covers, whenthe quick return mirror 46 is positioned at the retracted position, thequick return mirror 46 from below (i.e., from a side closer to theoptical path X extending from the object to the imaging unit 1). Thus,when the quick return mirror 46 is positioned at the retracted position,light entering from the finder optical system 6 is prevented fromreaching the imaging unit 1. The light shielding plate 47 serves as alight shielding section.

Specifically, the light shielding plate 47 includes a first lightshielding plate 48 pivotally connected to an end portion of the quickreturn mirror 46 located at an opposite side to the pivot axis Y, and asecond light shielding plate 49 pivotally connected to the firstshielding plate 48. The first light shielding plate 48 includes a firstcam follower 48 a. In the camera body 204, a first cam groove 48 b withwhich the first cam follower 48 a is to be engaged is provided. Thesecond light shielding plate 49 includes a second cam follower 49 a. Inthe camera body 204, a second cam groove 49 b with which the second camfollower 49 a is to be engaged is provided.

That is, when the quick return mirror 46 is pivotally moved, the firstlight shielding plate 48 is moved to follow the quick return mirror 46,and the second light shielding plate 49 is moved to follow the firstlight shielding plate 48. In this case, the first and second lightshielding plates 48 and 49 move in conjunction with the quick returnmirror 46 while the first and second cam followers 48 a and 49 a areguided respectively by the first and second cam grooves 48 b and 49 b.

As a result, when the quick return mirror 46 is positioned at theretracted position, as shown in FIG. 24(A), the first and second lightshielding plates 48 and 49 are arranged as a single flat plate below thequick return mirror 46, thereby shielding light between the quick returnmirror 46 and the shutter unit 42, i.e., the imaging unit 1. In thiscase, similarly to the quick return mirror 46, the first and secondlight shielding plates 48 and 49 are located off the optical path X.Therefore, the first and second light shielding plates 48 and 49 do notinfluence light entering the imaging unit 1 from the object.

As the quick return mirror 46 is moved from the retracted position tothe reflection position, as shown in FIG. 24(B), the first and secondlight shielding plates 48 and 49 arranged as a single flat plane arebent. When the quick return mirror 46 is pivotally moved to thereflection position, as shown in FIG. 24(C), the first and second lightshielding plates 48 and 49 are bent at an angle that allows them to faceeach other. In this state, the first and second light shielding plates48 and 49 are off the optical path X and are located at an opposite sideto the finder screen 61 across the optical path X. Therefore, when thequick return mirror 46 is positioned at the reflection position, thefirst and second light shielding plates 48 and 49 do not influence lightreflected toward the finder optical system 6 by the quick return mirror46 and light transmitting through the quick return mirror 46.

As described above, with the semi-transparent quick return mirror 46 andthe shielding plate 47 provided, in the finder shooting mode, the usercan view an object image with the finder optical system 6 beforeshooting is performed, and light can be caused to reach the imaging unit1. Also, when shooting is performed, incident light from the finderoptical system 6 can be prevented from reaching the imaging unit 1 bythe light shielding plate 47 while light from an object is directed tothe imaging unit 1. In the live view shooting mode, incident light fromthe finder optical system 6 can be prevented from reaching the imagingunit 1 by the light shielding plate 47.

—Operation of Camera—

The camera 200 configured in the above-described manner has the twoshooting modes, i.e., the finder shooting mode and the live viewshooting mode that employ different methods for viewing an object. Theoperations of the two shooting modes of the camera 200 will be describedhereinafter.

—Finder Shooting Mode—

First, the shooting operation of the camera system in the findershooting mode will be described hereinafter with reference to FIGS. 25and 26.

The power switch 40 a is turned on (Step S11), the release button 40 bis pressed halfway down by a user (Step S15), and then, the releasebutton 40 b is pressed all the way down by the user (Step Si11), so thatthe shutter unit 42 is temporarily put into a close state (Step Si12).The above-described Steps Si1-Si12 are basically the same as StepsSa1-Sa12 in phase difference detection AF of the first embodiment.

When the power switch 40 a is turned on, the quick return mirror 46 ispositioned at the reflection position on the optical path X. Thus, apart of light which has entered the camera body 204 is reflected andenters the finder screen 61.

Light which has entered the finder screen 61 is formed as an objectimage. The object image is converted into an erected image by thepentaprism 62, and enters the eye lens 63. That is, as opposed to thefirst embodiment, the object image is not displayed at the image displaysection 44, but the user can observe the erected image of the objectthrough the eye lens 63. In this case, the object image is notdisplayed, but various pieces of information regarding shooting aredisplayed at the image display section 44.

Then, when the release button 40 b is pressed halfway down by the user(Step Si5), various pieces of information (such as information regardingAF and photometry which will be described later, and the like) regardingshooting are displayed at the in-finder display section 64 which theuser can observe through the eye lens 63. That is, the user can identifyeach piece of information regarding shooting by not only the imagedisplay section 44 but also the in-finder display section 64.

In this case, since the quick return mirror 46 is semi-transparent, apart of light which has entered the camera body 204 is directed to thefinder optical system 6 by the quick return mirror 46, but the rest ofthe light is transmitted through the quick return mirror 46 to enter theshutter unit 42. Then, when the shutter unit 42 is put into an openstate (Step Si4), light transmitted through the quick return mirror 46enters the imaging unit 1. As a result, viewing the object image throughthe finder optical system 6 is allowed, and autofocusing by the imagingunit 1 (Steps Si6-Si8) and photometry (Step Si9) can be performed.

Specifically, in Steps Si6-Si8, phase difference detection AF isperformed based on an output from the phase difference detection unit 20of the imaging unit 1 and, in parallel with phase difference detectionAF, photometry can be performed based on an output of the imaging device10 of the imaging unit 1 in Step Si9.

In phase difference detection in Step Si6, the object image light istransmitted through the quick return mirror 46, and accordingly, anoptical length is increased by an amount corresponding to the thicknessof the quick return mirror 46. Thus, a phase detection width of thephase difference detection section defers between when the quick returnmirror 46 is retracted from an object image optical path and is put intoan image capturing state and when the quick return mirror 46 ispositioned at a reflection position. Therefore, in the finder shootingmode in which the quick return mirror 46 is interposed in the objectimage optical path, defocus information is output with a phase detectionwidth obtained by changing the phase detection width in phase differencefocus detection of the first embodiment (i.e., a phase detection widthin phase difference focus detection of hybrid AF in the live viewshooting mode which will be described later) by a predetermined amount.Note that the phase detection width means a reference phase differenceused for determining that a calculated defocus amount is 0, i.e., anobject is in focus.

Steps Si6-Si8 of performing phase difference detection AF is the same asSteps Sa6-Sa8 in phase difference detection AF of the first embodiment.

In Step Si9, the amount of light entering the imaging device 10 ismeasured by the imaging device 10. Note that in this embodiment, asopposed to the first embodiment, not the entire light from an objectenters the imaging device 10, and therefore, the body microcomputer 50corrects an output from the imaging device 10 based on reflectioncharacteristics of the quick return mirror 46 to obtain the amount oflight from the object.

Then, after the release button 40 b is pressed all the way down by theuser (Step Si11) and the shutter unit 42 is temporarily put into a closestate (Step Si12), in parallel with starting of image blur correction(Step Si13) and stopping down of the aperture section 73 (Step Si14),the quick return mirror 46 is flipped up to the retracted position inStep Si15.

Thereafter, in Steps Si16-Si18, similarly to Steps Sa15-Sa17 in phasedifference detection AF of the first embodiment, exposure is performed.

After exposure is terminated, in parallel with terminating of image blurcorrection (Step Si19) and opening of the aperture section 73 (StepSi20), the quick return mirror 46 is moved to the reflection position inStep Si21. Thus, the user can view an object image through the finderoptical system 6 again.

Thereafter, the shutter unit 42 is put into an open state (Step Si22).When a shooting sequence is terminated after resetting is completed, theprocess returns to Step Si5, and the body microcomputer remains in astandby state until the release button 40 b is pressed halfway down bythe user.

Steps Si23-Si25 after the power switch 40 a is turned off are the sameas Steps Sa21-Sa23 in phase difference detection AF of the firstembodiment.

As described above, the phase difference detection unit 20 for detectinga phase difference using light transmitted through the imaging device 10is provided to the imaging unit 1. Thus, even with the configuration inwhich light from an object is directed to the finder optical system 6 bythe quick return mirror 46 and thereby an object image can be viewedthrough the finder optical system 6, phase difference detection AF andphotometry can be performed in parallel while allowing the object imageto be viewed through the finder optical system 6 by employing thesemi-transparent quick return mirror 46 and thus causing a part of lightentering the quick return mirror 46 to reach the imaging unit 1.Therefore, there is no need to additionally provide a reflecting mirrorfor phase difference detection AF and a sensor for photometry, and also,photometry can be performed in parallel with autofocusing, so that arelease time lag can be reduced.

—Live View Shooting Mode—

Next, the shooting operation of the camera system in a live viewshooting mode will be described with reference to FIGS. 27 and 28.

First, in steps (Steps Sj1-Sj4) from the step in which the power switch40 a is turned on to the step in which the shutter unit 42 is put intoan open state, the same operation as the operation in hybrid AF of thefirst embodiment is performed.

In this case, in the camera 200, immediately after the power switch 40 ais turned on, the quick return mirror 46 is positioned at the reflectionposition, and thus, in Step Sj5, the body microcomputer 50 flips up thequick return mirror 46 to the retracted position.

As a result, light entering the camera body 204 from an object is notdivided to be directed to the finder optical system 6, but passes,through the shutter unit 42, is transmitted through the OLPF 43 servingalso an IR cutter, and then, enters the imaging unit 1. An object imageformed at the imaging unit 1 is displayed at the image display section44, so that the user can observe the object image through the imagedisplay section 44. A part of light which has entered to the imagingunit 1 is transmitted through the imaging device 10 and enters the phasedifference detection unit 20.

Then, when the release button 40 b is pressed halfway down by the user(Step Sj6), as opposed to the finder shooting mode, hybrid AF isperformed. Steps Sj7, Sj8, Sj11 and Sj12 according to this hybrid AF arethe same as Steps Sc6, Sc7, Sc10 and Sc11 in hybrid AF of the firstembodiment.

Note that the autofocusing method employed in this case is not limitedto hybrid AF, but contrast detection AF or phase difference detection AFmay be performed.

In parallel with hybrid AF, photometry is performed (Step Sj9), andimage blur detection is started (Step Sj10). Steps Sj9 and Sj10 are thesame as Steps Sc8 and Sc9 in hybrid AF of the first embodiment.

Thus, when the release button 40 b is pressed halfway down by the user,various pieces of information regarding shooting (such as informationregarding AF and photometry and the like) are displayed at the imagedisplay section 44.

Thereafter, the steps from the step (Step Sj13) in which the releasebutton 40 b is pressed all the way down by the user to the step (StepSj22) in which exposure is terminated to complete resetting arebasically the same as Steps Si11-Si22 in the finder shooting mode,except that the step (corresponding to Step Si15) of moving the quickreturn mirror 46 to the retracted position after the shutter unit 42 isput into a close state is not included, and that the step (correspondingto Step Si21) of moving the quick return mirror 46 to the reflectionposition after the shutter unit 42 is put into a close state toterminate exposure is not included.

According to this embodiment, when the power switch 40 a is turned off(Step Sj23), the focus lens group 72 is moved to the reference position(Step Sj24) and, in parallel with putting the shutter unit 42 into aclose state (Step Sj25), the quick return mirror 46 is moved to thereflection position in Step Sj26. Thereafter, respective operations ofthe body microcomputer 50 and other units in the camera body 204, andthe lens microcomputer 80 and other units in the interchangeable lens 7are halted.

The shooting operation of the camera system in the live view shootingmode is the same as the shooting operation of the camera 100 of thefirst embodiment, except the operation of the quick return mirror 46.That is, although hybrid AF has been described in the description above,various shooting operations according to the first embodiment can beperformed, and the same functional effects and advantages as those ofthe first embodiment can be achieved.

Therefore, according to this embodiment, the camera 200 further includesthe finder optical system 6 provided to the camera body 204 and thesemi-transparent quick return mirror 46, configured so that the positionof the quick return mirror 46 can be switched between the reflectionposition located on an optical path from an object to the imaging device10 and the retracted position located off the optical path, forreflecting a part of incident light at the reflection position to guidethe part of the incident light to the finder optical system 6 andcausing the rest of the incident light to pass therethrough to guide therest of the incident light to the imaging device 10. The body controlsection 5 is configured to be capable of switching a shooting modebetween a finder shooting mode in which shooting is performed in a statewhere an object can be viewed through the finder optical system 6 andthe live view shooting mode in which shooting is performed in a state inwhich an object can be viewed through the image display section. In thefinder shooting mode, the quick return mirror 46 is positioned at thereflection position to guide a part of incident light to the finderoptical system 6, thereby allowing an object image to be viewed throughthe finder optical system 6, and the rest of the incident light isguided to the imaging device 10 and focus adjustment is performed basedon a detection result of the phase difference detection unit 20 whichhas received light which has passed through the imaging device 10. Inthe live view shooting mode, the quick return mirror 46 is positioned atthe retracted position to cause incident light from an object to enterthe imaging device 10, thereby causing the image display section 44 todisplay an image based on an output of the imaging device 10, and focusadjustment is performed at least based on a detection result of thephase difference detection unit 20. Thus, in the camera 200 includingthe finder optical system 6, various types of processing using theimaging device 10 can be performed in parallel with autofocusing (theabove-described phase difference detection AF or hybrid AF) using thephase difference detection unit 20, regardless of which of the findershooting mode and the live view shooting mode is selected, so that theprocessing time can be reduced and also switching between the varioustypes of processing using the imaging device 10 and autofocusing thephase difference detection unit 20 can be performed quickly and quietly.As a result, the convenience of the camera 200 can be improved.

Moreover, with the semi-transparent quick return mirror 46 and theshielding plate 47 provided, in the finder shooting mode, beforeshooting is performed, an object image can be viewed through the finderoptical system 6, and light can be caused to reach the imaging unit 1.Also, when shooting is performed, incident light from the finder opticalsystem 6 can be prevented from reaching the imaging unit 1 by the lightshielding plate 47 while light from an object is guided to the imagingunit 1. In the live view shooting mode, incident light from the finderoptical system 6 can be prevented from reaching the imaging unit 1 bythe light shielding plate 47.

Other Embodiments

In connection with the above-described embodiments, the followingconfigurations may be employed.

Specifically, according to the second embodiment, the finder opticalsystem 6 is provided, but the present invention is not limited thereto.For example, a configuration including an electronic view finder (EVF),instead of the finder optical system 6, may be employed. Morespecifically, a compact image display section comprised of a liquidcrystal display or the like is arranged in the camera body 204 to belocated at a position where the user can view the image display sectionthrough the finder, and image data obtained in the imaging unit 1 isdisplayed at the image display section. Thus, even if the complex finderoptical system 6 is not provided, shooting while viewing through thefinder can be realized. In such a configuration, the quick return mirror46 is not necessary. The shooting operation is the same as that of thecamera 100 of the first embodiment, although two image display sectionsare provided.

In each of the above-described first and second embodiments, theconfiguration in which the imaging unit 1 is mounted on a camera hasbeen described. However, the present invention is not limited thereto.For example, the imaging unit 1 can be mounted on a video camera.

An example shooting operation of a video camera will be described. Whenthe power switch 40 a is turned on, an aperture section and a shutterunit are opened, and image capturing is started in the imaging device 10of the imaging unit 1. Then, optimal photometry and white balanceadjustment for displaying a live view are performed, and a live viewimage is displayed at the image display section. Thus, in parallel withimage capturing by the imaging device 10, an in-focus state is detectedbased on an output of the phase difference detection unit 20 mounted inthe imaging unit 1 and driving of the focus lens group is continuedaccording to the movement of an object or the like. In this manner, thevideo camera remains in a standby state until a REC button is pressedwhile continuing to display a live view image and to perform phasedifference detection AF. When the REC button is operated, image datacaptured by the imaging device 10 is recorded while phase differencedetection AF is repeated. Thus, an in-focus state can be maintained atall the time, and as opposed to a known digital camera, micro driving ofa focus lens in an optical direction (wobbling) does not have to beperformed, so that an actuator such as a motor and the like, which has alarge electric load, does not have to be driven.

Also, the configuration in which when the release button 40 b is pressedhalfway down by the user (i.e., the S1 switch is turned on), AF isstarted has been described. However, AF may be performed before therelease button 40 b is pressed halfway down. Moreover, the configurationin which AF is terminated when it is determined that an object image hasbeen brought into focus has been described. However, AF may be continuedafter focus determination, and also AF may be continuously performedwithout performing focus determination. A specific example will bedescribed hereinafter. In FIGS. 11 and 12, after the shutter unit 42 isopened in Step Sa4, phase difference focus detection of Step Sa6 andfocus lens driving of Step Sa1 are performed repeatedly. In parallelwith this operation, determination of Step Sa5, photometry of Step Sa9,image blur detection of Step Sa10, and determination of Step Sa11 areperformed. Thus, an in-focus state can be achieved even before therelease button 40 b is pressed halfway down by the user. For example, byusing this operation with live view image display, display of a liveview image in an in-focus state is allowed. If phase differencedetection AF is used, live view image display and phase differencedetection AF can be used together. The above-described operation may beadded as a “continuous AF mode” to the function of a camera. Aconfiguration in which the “continuous AF mode” is changeable between onand off may be employed.

In each of the above-described first and second embodiments, theconfiguration in which the imaging unit 1 is mounted in a camera hasbeen described. However, the present invention is not limited to theabove-described configuration. The camera in which the imaging unit 1 ismounted is an example of cameras in which exposure of an imaging deviceand phase difference detection by a phase difference detection unit canbe simultaneously performed. A camera according to the present inventionis not limited thereto, but may have a configuration in which objectlight is guided to both of an imaging device and a phase differencedetection unit, for example, by an optical isolation device (such as,for example, a prism, a semi-transparent mirror, and the like) forisolating light to the image device. Moreover, a camera in which a partof each microlens of an imaging device is used as a separator lens andis arranged so that pupil-divided object light can be received at lightreceiving sections may be employed.

Note that the above-described embodiments are essentially preferableexamples which are illustrative and do not limit the present invention,its applications and the scope of use of the invention.

INDUSTRIAL APPLICABILITY

As has been described, the present invention is useful particularly foran imaging apparatus including an imaging device for performingphotoelectric conversion.

1-20. (canceled)
 21. An imaging apparatus, comprising: an imagingsection configured to convert light into an electrical signal byphotoelectric conversion to output the electrical signal; a phasedifference detection section configured to receive light to performphase difference detection; and a control section configured to controlthe phase difference detection section to allow the phase differencedetection section to perform the phase difference detection in parallelwith obtaining an output from the imaging section.
 22. The imagingapparatus of claim 21, further comprising a display section configuredto display an image, wherein the control section allows the displaysection to display an image based on the output from the imaging sectionin parallel with controlling the phase difference detection section toallow the phase difference detection section to perform the phasedifference detection.
 23. The imaging apparatus of claim 21, furthercomprising a focus lens configured to adjust a focus position, whereinthe control section is configured to perform focus adjustment usingcontrast detection based on the output from the imaging section anddetermines, based on a detection result of the phase differencedetection, a direction in which the focus lens is driven when driving ofthe focus lens is started in the focus adjustment.
 24. The imagingapparatus of claim 21, wherein the control section detects a contrastvalue of an image based on the output from the imaging section andperforms, when the contrast value is equal to or larger than apredetermined value, focus adjustment at least based on a detectionresult of the phase difference detection section, and performs, when thecontrast value is smaller than the predetermined value, focus adjustmentnot using the detection result of the phase difference detection sectionbut based on the output from the imaging section.
 25. The imagingapparatus of claim 21, further comprising an imaging apparatus body inwhich the imaging section, the phase difference detection section andthe control section are provided; and an interchangeable lens attachedto the imaging apparatus body so as to be removable, wherein when theinterchangeable lens is a reflecting telephoto lens and a product madeby a different manufacturer from a manufacturer by which the imagingapparatus body is made, the control section performs focus adjustmentnot using a detection result of the phase difference detection sectionbut based on the output from the imaging section, and when theinterchangeable lens is not a reflecting telephoto lens or is a productmade by the same manufacture by which the imaging apparatus body ismade, the control section performs focus adjustment at least based onthe detection result of the phase difference detection section.
 26. Animaging apparatus, comprising: an imaging section configured to convertlight into an electrical signal by photoelectric conversion to outputthe electrical signal; a phase difference detection section configuredto receive light to perform phase difference detection; and a controlsection configured to perform photometry using the imaging section inparallel with controlling the phase difference detection section toallow the phase difference detection section to perform the phasedifference detection.
 27. The imaging apparatus of claim 26, furthercomprising a focus lens configured to adjust a focus position, whereinthe control section is configured to perform focus adjustment usingcontrast detection based on an output from the imaging section anddetermines, based on a detection result of the phase differencedetection, a direction in which the focus lens is driven when driving ofthe focus lens is started in the focus adjustment.
 28. The imagingapparatus of claim 26, wherein the control section detects a contrastvalue of an image based on an output from the imaging section andperforms, when the contrast value is equal to or larger than apredetermined value, focus adjustment at least based on a detectionresult of the phase difference detection section, and performs, when thecontrast value is smaller than the predetermined value, focus adjustmentnot using the detection result of the phase difference detection sectionbut based on the output from the imaging section.
 29. The imagingapparatus of claim 26, further comprising: an imaging apparatus body inwhich the imaging section, the phase difference detection section andthe control section are provided; and an interchangeable lens attachedto the imaging apparatus body so as to be removable, wherein when theinterchangeable lens is a reflecting telephoto lens and a product madeby a different manufacturer from a manufacturer by which the imagingapparatus body is made, the control section performs focus adjustmentnot using a detection result of the phase difference detection sectionbut based on an output from the imaging section, and when theinterchangeable lens is not a reflecting telephoto lens or is a productmade by the same manufacture by which the imaging apparatus body ismade, the control section performs focus adjustment at least based onthe detection result of the phase difference detection section.